All of K. A. Applegate's series (Animorphs and Everworld, for the benefit of nonfans) use the "indirect quotation" route. Things like "Jake sat up straight and said a word you really shouldn't say in class," or merely referring to "words I won't repeat." It actually seems like a good way of compromising between actual cussing on the one hand, and the Gosh Dang It to Heck! style on the other.
Remnants, Applegate's third junior scifi series, gets to say "jackass" and "damndest" once each, but that's it. Considering the fact that the world blew up and there's a giant sentient spaceship trying to kill them, you'd think there'd be more of this at least, but unlike the previous series, this one isn't written in the first person.
Many of Dave Barry's newspaper columns noted that certain words in quotes were replaced with euphemisms to avoid offending family audiences. These euphemisms could be Inherently Funny Words or proper names from context, but usually they were obvious soundalikes, such as "duck shoe." Dave Barry's novels Big Trouble and Tricky Business use actual dirty words, as the author warns at the beginning of both.
After a column he did on Beano was left out by a couple of newspapers, he did a column on circumcision. He explained it as someone "taking hold of a guy's Oregonian and snipping his Post-Dispatch right off."
Upon discovering that they had named their new cigarette spokesperson "Dave," Barry wrote a column using Phillip Morris CEO Geoffrey C. Bible's name as a euphemism.
"Honey, the dog made Geoffrey C. Bible on the carpet again!"
H. Beam Piper showed one way this could come about in the short story "Naudsonce". It features an exploratory team of humans landing on an inhabited planet to find that the inhabitants seemed to have four different words for "me" - fwoonk, pwink, tweelt, and kroosh. A fair amount of time later, they were no closer to translating the local language, and the expedition's military contingent had begun using those four words as profanities. It turns out the aliens had a unique "nonauditory sonic sense", or naudsonce, that essentially let them feel sound.
By the first shell: The first Hatching is of noteworthy importance to those who revere dragonkind. They swear by the beasts and men who protect them from danger of Threadfall. Many Pernese oaths are of a similar character, in which a rider will p
"Through Fog, Fall, and Fire" is reminiscent of the vow of the American postman, who promises to deliver the mail "through rain and sleet and dark of night." Like a good Celtic triad, it names three disasters or trials through which one must pass to prove faith.
The outdoor humorist Patrick McManus sometimes details adventures with his (fictional) neighbor, who calls people he dislikes "crude anatomical names." Like "elbow", or "kneecap". McManus also sometimes uses "bleep" in a humorous fashion, as in this example from his (again, fictionalized) childhood: "'Bleeping bleep of bleep!' he screamed, introducing me to that quaint phrase for the first time."
The Council Wars series uses the word "fisk" to replace a similar word starting and ending the same way.
The Prince Roger series, co-authored with David Weber, uses "maulk" for shit and "grap" for fuck. Poertena, the Pinopan armorer tends to use "pock" a lot, like for example calling his characteristic tool a "pick pocking wrench". While "pock" is his Funetik Aksent , the rest of the company adopts the term as well.
Several of Spider Robinson's stories have "slot" as an insulting epithet for a woman, often in the phrase "taken slot" (substituting for "fuckin' slut"). Robinson also uses the word "kark" in place of "fuck," even in stories set five minutes in the future.
Robert Anton Wilson, in his late-1980s Schrödinger's Cat novels, used the names of the then-current political figures and feminists in place of various more explicit words, turning what might have been seen as dirty language for the sake of dirty language into a masterful piece of political satire. Thus, breasts are referred to as (Susan) Brownmillers, orgasm as (Kate) Millett, and excrement as (Warren) Burger (this last is particularly hilarious in a gag involving a chain letter about fertilizing your lawn by getting strangers to Burger on it).
This one originated with Gore Vidal's Myron (the sequel to Myra Breckinridge). In the original version of the book, Vidal replaces all the swear words with the names of Supreme Court Justices who had just voted in favour of some pro-censorship measure or other. So we have Burger = bugger, Father Hill = tit, Rehnquist = dick and so on. The euphemisms were dropped when Myron was re-released in a compilation volume with Myra (which never bothered with such things).
Examples aimed at book series and literature renditions of franchises
The dialog in the Codex Alera series involves a lot of creative variations on "crows" and "furies." Among other things, this has led to one character earning the Fan Nickname "the Crowbegotten Batman."
"Seamstress" has become an Unusual Euphemism for "prostitute" in Ankh-Morpork ("They call themselves 'seamstresses'... hem-hem!"). This often leads to confusion, and as such actual seamstresses are in short supply in the city. The Seamstress Guild leader is Ms. Rosie Palm.
Truth in Television: In days when self-employed women were rare, ladies of the night faced with reporting their income for taxes would claim that they were seamstresses, a self-employed profession that was acceptable for a woman.
In a few books, one's first tryst is described as "moving your world". It's specifically invoked for Carrot's first time with Angua in Men at Arms with an add-on joke: "And didn't even bother to stop to cancel the bread and newspapers."
In Guards! Guards!, a nervous Fred Colon remarks "I'll be mogadored!" when he spots Errol the swamp dragon and thinks Captain Vimes has captured the noble dragon that's been terrorizing the city. Said phrase is later used in Maskerade, when Nanny Ogg is so flabbergasted at the sight of Granny Weatherwax dolled up for the opera, "I'll be mogadored!" is the only oath she can think of.
The Truth contains an example which is also a Running Gag complete with its own Lampshade. The thug Mr Tulip uses the swearword "—ing" in every sentence. As in, "A —ing werewolf? Are you —ing crazy?" At one point, this prompts another character to wonder how he manages to pronounce the dash. Later in the book, the very prim and proper Sacharissa ends up threatening a character with a gun and the words, "Let us use your 'ing' presses or I'll 'ing' shoot your 'ing' head 'ing' off!" - adding, "I think that's how you're supposed to say it, isn't it?" (Followed on the next page by, "What a silly girl I am. 'Ing'. I feel so much better for saying that, you know? 'Ing'. 'Inginginginginginging'. I wonder what it means?") Strangely, other characters' replies at various points only make sense if he is using an actual swearword.
Apparently he has a "speech impediment".
Combining "Plonker" with "todger" gives us the term "tonker", originally supposed to be dwarfish, but now firmly entrenched in Morporkian, much as certain Yiddish terms found their way into Cockney.
In Guards! Guards!, a cult leader has his underlings swear an oath of loyalty, on pain of, among other things, being "strung up by one's figgin". None of them even ask what a "figgin" is.
Lord Vetinari reflects on a historical reference to a man being strung up by his figgin (after a figgin has been revealed to be a small bun with currents in it) that either the language has changed or there is something very unpleasant about a man being suspended beside a tea-cake.
A somewhat weird example occurs in The Last Continent, where the Chair of Indefinite Studies expresses the opinion that bridge would work better for procreation than sex. When reminded that this would need at least four people, he suggests croquet instead, and states that he has indeed "enjoyed a quiet knock-about all by [him]self." Cue slow edging away from the Chair.
Various characters are described as going "librarian poo". The Librarian of Unseen University is an orangutan (an ape).
The Tiffany Aching books are usually preluded by a short glossary of Nac Mac Feegle terms, compiled by a rather prim and proper witch. As a result, the entry for "pished" reads: "I am assured that this means tired."
In Thief of Time, one of theAuditors starts out using curse words like "Discord!" and "Confusion!", but feels the need for something... coarser. Hence: "Do as I say, you organic organ!"
Interesting Times uses "complicated pictogram", often with a minimally-provocative description following. (The equivalent of an exclamation point is a urinating dog. This has been used up to four times in a row.)
Eric made a Running Gag about a crude-mouthed (and featherless) parrot that shouted "wossname" all the time. Thing was, half the time, the parrot was referring to a man's genitals (which part was implied by whether or not the parrot spoke in plural—"...got you by the wossnames.." vs. "It'll turn your wossname.").
In several books, various members of the Watch have averted this with the phrase 'prodding buttock'. This is similar to kicking ass, but much less forceful, so it doesn't count as a euphemism.
The Doctor Who Virgin Publishing Expanded Universe novels had the term "cruk". In one book a character from the mid-21st century claims it's from a kids' TV series and means "tired", but the Doctor says that by the 24th century (where his companions picked it up) it means "something very rude indeed".
The novels were also fond of using "spack" as a multi-purpose cussword. It actually derived from a fluffed line in the original series story "Destiny of the Daleks" where, trying to say "Stay back" or "Back off", the Doctor ends up shouting "Spack off!" to some Daleks. In the early days of the novels series, real-life words were used. Repeatedly. To the point where the BBC stepped in and told them they weren't allowed to use the F-bomb any more, or they'd lose their license. (Later on, they did lose it.)
In the Eighth Doctor Adventures, this exchange occurs, and makes you glad the TV series uses "dancing":
Literary/film example: The first time we ever see Hermione in the Harry Potter and the Philosopher's Stone, she says "Holy cricket, you're Harry Potter!" A more direct example would be the insult "Mudblood", relating to pureness of blood, which seems to be analogous to a racial slur and is considered very offensive in the Wizarding World. Another way this is avoided is to have a character's dialog stated indirectly in the narrator's voice - as in, "Ron cursed loudly."
One minor character in The Eternal Ice uses the phrase "What the phrex?", obviously short for Phyrexia. Unlike most Unusual Euphemisms, this one was only used once. Sometimes other curses are used that refer to Phyrexia, such as "the nine hells." Considering what Phyrexians are and what they've done to Dominaria over the millennia, it's reasonable Dominarians would have curses like these.
Characters in Clayton Emery's novels tend to use names of cards and characters, such as "Eye of Orms-by-Gore!"
In Bruce Coville's My Teacher... science fiction series, one of the characters is implanted with a Universal Translator that can interpret every word, gesture or inflection that the various alien characters use to communicate. However, an alien named Kreeblim is known to use the word "plevit", which his translator has no English equivalent for, and which is implied to be incredibly rude.
A Series of Unfortunate Events: On two occasions, flustered or frightened characters blaspheme the names of divine entities from about five different religions, concluding with "Charles Darwin!" or "Nathaniel Hawthorne!"
Star Wars mostly stuck to "damn" and "hell", at least from the human characters, but the Star Wars Expanded Universe features a wide variety of made-up profanity. Some of it is a thinly disguised substitute for real-world swearing, such as "shavit" in which the middle two letters might as well not be there. The word "kriff" (invented by Timothy Zahn in one of the better EU novels) seems to be used as a substitute for "fuck" in all its contexts, especially on some of the stricter Star Wars fan forums that don't allow Earth-based expletives. One site doesn't even allow initialisms that suggest the word "fuck", as a result of which such terms as WTK, KUBAR and SNAKU are widely used and understood. Unfortunately, which words each character uses is one of the many things authors don't share with each other, so there are a lot which only come up in a particular book or series, which implies that specific swear words spread, meme-like, and are replaced over a very short period of time.
His more recent story Allegiance, by virtue of being about a bunch of navy men and pirates, is littered with all kinds of krinking swears. It's a bit strange to hear Han Solo "swearing" in front of Leia like that. Zahn also uses "fusst," and has a stormtrooper wondering "What in the worlds?"
Leia famously calling Han Solo a 'scruffy looking nerf herder'. Wookiepedia explains it. They are unpleasant beasts indeed.
In the X-Wing Series in particular, various uses of the word "sith" are popular as well, sithspit, sithspawn, son of a Sith, the whole sithing gamut. Made more confusing because "Sithspawn" also applies to various monsters created by the Force. Weirdly, it never gets applied to Luke or Leia, although it would be entirely appropriate.
Possibly because they were conceived before Anakin actually turned and he'd been redeemed by the time everyone found out. If what's been said about Darth Plagueis and Shmi Skywalker is true, though...
A line in I, Jedi indicates that the Skywalkers tend to keep their heritage secret, for reasons that should be fairly obvious.
"Spast" is a fun one but "stang" is one of the oldest ones, showing up VERY early on, as a popular Alderaanian swear word. "Mudcrutch" is popular too, for "bastard" or such words, and "Kath hound", a Star Wars-universe animal, works for "bitch". "Kark" seems to be another substitute for various curses, and was notably used more in the Old Republic. e.g.: "Kark on you, Jedi," and "We're karked!" We've also got "scragged" and the rather inexplicable modifier "milking", as in "We're milking scragged!"
The Huttese term "E chu ta" was invented for the Star Wars universe, and is actually used by a protocol droid on Cloud City at C-3P0, who responds aghast "How rude!" I think it was Ben Burtt who created it, but I may be wrong. Considering the context it is used in, and the way it is described by the creator, the most likely translation for it would be "Fuck you".
Perhaps inevitably, "frak" has made its way into the Star Wars universe, apparently courtesy of Michael Kube-McDowell who uses it in the Black Fleet Crisis Trilogy.
There's also "rodder" (Kriffin' rodders!), and the decidedly hilarious "lube" (He got lubbed!). There was also another from the Dark Nest books which was an obvious stand-in for "fuck", since there was a whole "Mommy, what does mean?" bit between Mara and young Ben.
Karen Traviss once condemned about half of the existing swear words - all the ones that get said as an expression of surprise - including "Stang" and "Bloah", claiming that all real profanities had to be sharp-sounding and easy to say! Like "fierfek" and "di'kut". ...People paid about as much attention as you'd expect.
"Poodoo!" seems to be a common profanity in the Star Wars Universe, and although it is translated as "fodder" in the movie subtitles, I'm sure we can all guess what it really means.
In the novelization of Starship Titanic, The Journalist tends to use the word "Pangelin" (sometimes "Purple Pangelin"), which is the Blerontinian equivalent of "shit", we're assured in the footnotes. He also finds out one of the female characters is named "Lucy," and reacts with a start; he refuses to tell her what it means in his native language, even after they get married.
Peter David gave his Xenexian captain the curse word "grozit", which is about what you'd expect. Also, David is one of quite a few to use "Kolker" as a swear word on par with "Jesus Christ" or "God". Apparently a lot of writers revere Robert Kolker.
At least one novel has an example: to the Ferengi, "Charity" is the equivalant of dropping an F-Bomb.
The Warhammer 40,000Gaunt's Ghosts novels have Tanith characters use the terms "feth" and "fething". The word Feth actually refers to a tree spirit, but is used in all contexts exactly like another four-letter word beginning with F, even to the point that anti-tank rocket launchers are nicknamed "tread-fethers" - although, as Gaunt tells an Inquisitor in Ghostmaker, apparently not the sexual connotations. The newer recruits from Verghast use "gak", and it's said that Gaunt knows the regiment has knit together when the two groups start using each others' swearwords. Other novels include such gems as "kec" and "nink", along with appropriated terms such as "frag" and "frakk". It seems that every world in the Imperium has its own unique curse of choice.
Blood Pact has a rather long one, when a certain criminal gets angry.
Xomat graphically outlined something that Daur might like to do, provided he could find a number of specialist agricultural items, some livestock, and a means of contacting an elderly female relative at short notice.
"Frak" is used in the Ciaphas Cain books, as a deliberate shoutout.
"Frakking Warp" is considered a barracks-room oath. Naturally, we first hear this from a noblewoman.
The Imperium as a whole has a variety of other phrases, largely replacing religiously-inclined curses, Including oaths such as "Emperor on Earth", a variety involving the word "Throne" ("Throne Damn It", "Golden Throne!" and so on), and the best of all: "Emperor's Bowels!"
In An Abundance of Katherines, the main characters use "fug" and its derivatives (fugging, fugger, etc). They explain that this was taken from a war novel where the publishers wouldn't allow the F-bomb to be used.
In Frank McCourt's memoir, Angela's Ashes, his teenage self refers to sexual relations as "the excitement". He and other members of his family refer to his conception (which was up against a wall) as a "knee trembler".
In the Artemis Fowl books, a common expletive is D'Arvit, which is revealed to be a curse that is untranslated from the fictional fairy language in order to avoid censorship.
A clever use of one of these turns up in Aunt Dimity and the Village Witch. As part of an early skirmish against Mae Bowen's hippie fans, Peggy Taxman accuses one Bowenist of this in Aunt Dimity and the Village Witch. From her outraged response, he said something about her "petals", and she took it to mean her labia. Definitely Played for Laughs, but the laugh's on the cultist.
In the world of David Eddings's Belgariad and Malloreon, Angaraks have taken to refer to their maimed god, Torak, when making curses. "Torak's teeth!" and "By Torak's boiling eye!" are pretty common among them, even after Torak was slain at the end of the Belgariad.
Book of the Short Sun: After the protagonist has come home from a very long trip, the local priest wishes to know if he engaged his wife in the-hum-"warm commerce".
In Wen Spencer's A Brother's Price, Jerin is noted as being skilled at k'lamour (italics in text) or oral sex, from the context. This term is only used once, and it's in a novel with no other constructed language to speak of. As the word is a kind of mangled Latin, or French (amour = love), it could also mean sex in general. It is referred to as "the paths of pleasure". Jerin is extremely embarassed about having to talk about it. Normal sex that is provided by the husband for his wives is called "servicing" the wives, which is also unusual, although your mileage may vary on whether it is an euphemism.
"Dirty Pillows" is a euphemism for breasts in Carrie.
In Chess with a Dragon, the backstabbing culture of the InterChange is such that "interesting" has become a euphemism for "dangerous", on the basis that a matter of survival is always interesting.
C.S. Friedman's Coldfire Trilogy uses "vulk", as in 'vulcanism' - since volcanic activity can stir up the planet's fairly unpleasant magic.
In The ColSec Trilogy, Heleth says "yeck" both as the obvious replacement for "ew" and as an apparent euphemism (calling things that she dislikes "yecky" and people who annoy her "yeck-head," to give some context) for "shit." Often.
Ellie Arroway, protagonist of Contact, says "Holy Toledo!" when she's shocked but other people are around. When they're not, as in when the Very Large Array has picked up what looks like a genuine message from extraterrestrial intelligences, she carefully sequesters herself for just a moment and whispers "Holy shit!"
The Culture, due to its nature as a machine and biological society, has several curses devoted specifically to describe AI's. "Meatfucker" is a common one for an AI that somehow transgresses a biological (usually through mindreading). Less frequently, biologicals use the word "Motherjunk" to describe drones who misbehave.
Rodrick and Greg have several of these so their mom doesn't catch them swearing, like "spooky stork" and "raspberry plastic tickle bear". Greg has to be careful not to embarrass himself by accidentally saying these words at school.
"Ploopy"—we don't know what it means, but Greg's baby brother Manny considers to be quite offensive.
Apparently, in Fregley's secret language, "juice" means "I have to go to the bathroom."
Orson Scott Card's novella "Dogwalker" (collected in Maps in a Mirror) is full of cyberpunk-style slang, and has a character use the word "pope" to mean "penis." Later a character is described as being "smart enough to put his hands in his pockets without seeking an audience with the pope."
Given that Card is a member of the LDS Church, this could be seen as a Take That! to Catholicism...
In Britain at any rate, "bishop" can be used as a euphemism for "penis" ("bashing the bishop" being one slang term for jerking off) since the bishop in a chess set looks vaguely like the organ in question. There is also at least one example of "cardinal" being used (in Aleister Crowley'sNot the Life of Roger Bloxam.) Presumably Orson just took the idea to its logical conclusion...
In the Dream Park novels by Larry Niven and Steven Barnes, "drown" is now a swear-word in a California that has suffered through a particularly massive earthquake.
The Dresden Files has a few of these; Harry typically uses "Stars and stones" or "Hell's bells" when exasperated/surprised/frustrated, and the incubi and succubi of the White Court tend to use, "Empty night..." in the same context. Word of God states that the last three books in the series will be an apocolyptic trilogy titled "Stars and Stones," "Hell's Bells" and "Empty Night." Jim Butcher has gone on the record stating "They're swears for a reason."
Frank Herbert's Dune, at least on one occasion, replaced the f-bomb with "floggin'". The author was perfectly happy to use other cuss words through the series, but even "flog" isn't used again for the series.
Grignr from The Eye of Argon occasionally uses "Mrifk!" as a swear word, which doesn't seem to have an English- (or any-) language equivalent. His enemies also liberally throw around the word "Slut!" with both men and women alike, for whatever reason. "Mrifk" is evidently a being of some sort, given that Grignr swears "by the surly beard of Mrifk" near the beginning. Beyond that, it's unclear who or what it is.
In Ysabeau Wilce's second novel of the Flora Segunda series, Flora's Dare, it becomes clear that the Republic of Califa's preferred four-letter word is "fike". This is a disappointment after the first book's more imaginative exclamations, such as "Pigface Psychopomp!"
In the novels about Elijah Baley, he uses the expletive "Jehoshaphat!"
In Friday by Robert A. Heinlein, slitch is a term of opprobrium directed at some females. While the meaning is unclear, it would make perfect sense to view it as a portmanteau on "slut" and "bitch".
Garrett, P.I.: In Deadly Quicksilver Lies, Winger describes her employer's gang as "the kind of guys who wear earrings", and Garrett semi-sarcastically remarks that they might be ferocious pirates. For the rest of the novel, Garrett refers to the Rainmaker's mooks and associates as "pirates", even when it's clear that, yes, this particular crime boss operates through TunFaire's homosexual community.
Gone: The kids come up with a few terms to describe what happens when people turn 15 and disappear. Some of the more frequently-used ones are "poof", "blink", and "make the jump". Basically, they're all just euphemisms for dying.
Good Omens: The demon Crowley, being a demon, finds religious swears to be inappropriate, but doesn't want to use the Devil's name for fear of getting his attention, leading to phrases like 'oh, for Someone's sake'.
A line in the book claims that 'angels are sexless unless they really want to make an effort', leading to fandom adopting 'effort' as a euphemism for (usually male) genitalia, and 'making an effort' for arousal.
Haunted by Chuck Palahniuk: "Pearl Diving" is Saint Gut-Free's term for underwater masturbation.
In the original radio play and the American version of Life, the Universe and Everything, the word "Belgium" is recognized everywhere in the Universe except on a certain Insignificant Little Blue Planet as such a rude word that it's only used in serious screenplays (one character has an award for Most Gratuitous Use of "Belgium" in a Serious Screenplay). The UK version of the book simply used "Fuck", but the "Belgium" joke seems to be more popular with many readers. For the same reason, the American edition of Life, the Universe, and Everything borrowed "swut" from the radio series, and changed an insult for Arthur Dent from "arsehole" to "kneebiter" (again, some readers prefer the latter).
The name of The Great Prophet Zarquon is also taken in vain occasionally. The term "zark", used in similar contexts as "fuck" (e.g. "zarking", "zark off"), was said by Douglas Adams to have been derived from this.
"Photon" and "dingo's kidneys" (occasionally "flying dingo's kidneys") were also used for swearing, mostly by Zaphod in the radio series.
In one radio episode, Beeblebrox swears "Holy Zarquon's singing fish", bringing on persistent interrogation by Ford as to what singing fish have to do with Zarquon, and why is he saying it anyway?
In John Krakauer's Mt. Everest memoir Into Thin Air, the Sherpas giggle and exclaim that two characters are "sauce-making, sauce-making!"
In some stories, the characters use "TANJ", which stands for "There Ain't No Justice". There may also be an occasional TANSTAAFL ("There Ain't No Such Thing As A Free Lunch").
In others, the characters curse - and mean it! - by using the literal words censored and bleep. Apparently, the media of his universe had never relaxed the censorship that ours started with, and the replacement words stuck. This is lampshaded in the novella The Defenseless Dead when one character explains that 'censor' and 'bleep' were originally euphemisms for words which they wouldn't let you use, and not actual expletives. It's also pointed out that 'damn' was originally "a technical term in theology".
The use of Unusual Euphemisms in Science Fiction dates back at least as far as the 1930s, where the galaxy-spanning heroes of E. E. “Doc” Smith's Lensman saga were prone to swearing by the iridium intestines, carballoy claws, and other metallic body-parts of the "spaceman's god", Klono - making this Older Than Television, and an integral part of the Space Opera subgenre since its genesis. Indeed, Klono is popular among spacemen because of his plethora of adjectival bodyparts, making it easy to swear by him. Smith also wasn't above swiping from Yiddish - Kim Kinnison once accuses Nadreck of just sitting around on his "spiny tokus" (= tucchus = rump - if Nadreck actually has such a thing, being a 4th-dimensional Palainian....)
Arthur Herzog's Make Us Happy is set in a computer-run utopia where the computers merged all the important swear words for simplicity. They ended up with "fusb".
In The Maze Runner, the Gladers have several of these. "Klunk" means "feces," "shank" means "guy," and "shuck" is just an all-purpose euphemism.
Finn's Mister God, This Is Anna includes a tough Cockney demanding to know which of the "Sodden Baskets" in the pub has nicked his bangers and being told to "Mind yer language, there's a nipper 'ere."
In one really weird subversion or inversion, Niven and Pournelle's The Mote in God's Eye simply avoids the euphemism altogether as characters just flat-out use the word "rape" in places one would expect a different four-letter word that starts with f.
The publisher of Norman Mailer's The Naked and the Dead famously persuaded the author to replace all occurrences of the f-word with "fug." In an apocryphal story, Dorothy Parker (or Tallulah Bankhead, in some versions) introduced herself to Mailer later with, "So you're the young man who can't spell 'fuck.'"note The use of "fug" in The Naked and the Dead inspired the name of the '60s rock band The Fugs, who preferred the uncensored version of the word in many of their songs.
In one of the Narnia books, a talking dog says that its kind call their puppies "boys" when they're being naughty. Another dog adds that "girls" is also used, but is shushed by the other dog because the term is considered so very rude.
The kids in the Origami Yoda series replace profanities with names of characters and things from Star Wars, i.e "What the Fett?" note Boba Fett is a character from Star Wars.
Jane Yolen's Pit Dragon Chronicles uses "fewmets" (the term for the caustic manure of a dragon) as a swear word.
In some of Tamora Pierce's Provost's Dog books, characters use words that are clearly meant as swears but which don't sound like it to modern ears, like "sarden" and "pox-ridden," along with "swive/swiving" in place of "fuck/fucking." Most of these are actual words pulled from historical slang dictionaries ("swive" is used frequently and with glee by Geoffrey Chaucer, among others). It is possible that Pierce managed to get this word past the censors simply by virtue of using so many other actual Unusual Euphemisms in the book. Sandry, the stitch witch in the "Circle of Magic" books says "Cat dirt!" when sorely vexed.
Redwall novels: When we finally see Grood in Lord Brocktree use the bad language Jukka has repeatedly berated him for, it's apparently in squirrel dialect: "Gorokkah! How'd that splitten flitten gurgletwip get up so high?"
In the Ringworld series of novels, the denizens of said ring have "flup" as a curse, which actually refers to seabottom ooze. The emphatic form is "odorous flup".
The Ripliad book Ripley Under Water. Earlier in the novel, he is looking at travel advertisements and is amused by the actual Thai island, Phuket. Later, when really angry, he thinks out loud Phuket!note This is actually used incorrectly in the story. It is actually pronounced 'Poo-ket', rather than like the profanity it resembles. Whether this falls in to Aversion or Subversion is up to others, and may depend on if the author knew how to pronounce it.
Rone Leah from Terry Brooks's Shannara series frequently says "For cat's sake!".
Gregory Maguire named his second Wicked book Son of a Witch. Shiz University, a very clever incarnation of this trope.
In A Song of Ice and Fire, characters say "Seven Hells," referencing the seven new gods. Also, swearing "by the old gods and the new," and occasionally a phrase like "Others take it!" Otherwise, though, they tend to stick to contemporary curse words.
This is even lampshaded in the series, when at least one character's internal dialog mentions having no idea why this is a rude thing to say.
Holly Lisle's Talyn, a fantasy, includes "pogging" to refer to sex. The character's a soldier, so she uses it quite a bit.
In Teenage Worrier Letty Chubb suffers panic attacks upon merely seeing the word "de-", oops, "the word about dying that rhymes with breath" written down, and in her diaries she always uses "banana" instead. She mentions that she tries to find creative ways to avoid it in essays, but "phrases like 'hurtling into the chasm of doom' not appropriate for life cycle of tadpole". She also uses the term "pluke" both to refer to her pimples and as an expletive.
In one book, she considered "raincoat" as her new alternative word for death; but said that even she found this one too silly.
The Gripping Hand (The sequel to The Mote in God's Eye) by Larry Niven and Jerry Pournelle uses an Unusual Euphemism as a plot point. In order to prove they haven't been replaced by master-psychologist aliens (who haven't been in contact with humans in years) some characters use the recently invented curse "rape my lizard!", with the justification that profanity-evolution is essentially random, and won't be predicted by the aliens.
In The High King, the final volume of the Chronicles of Prydain, the outlaw Dorath informs Princess Eilonwy that he intends to "remove your charms" "until you are fit company for a swineherd," referring to the hero Taran. What he means is that she's going to be gang-raped by his band of thugs. The odd wording is to keep from traumatizing younger readersnote The Chronicles of Prydain books are intended for older children and would be found in the Young Adult section of a library, so sensitivities had to be considered., who can understand that she's in danger without knowing exactly what's going to happen; older readers can figure it out, as Eilonwy did.
The Temporal Void has this rather chilling reference to (the 39th century's hyper-advanced) torture techniques as "today's medical techniques".
Several characters in Thieves' World are heard using the word "frogging" instead of another f-word.
Neil T. Stacey's Trespasser's will be prostituted, set about 100 years in the future, introduced the word "vampire" as a euphemism for a homosexual. Most readers interpret this as a subtle jab at the Twilight fandom. This is carried over into Stacey's newer book, Kill Time or Die Trying.
Vatta's War uses "Heavy Machinery" as a euphemism for "Big Honkin' Spaceguns". This leads to some awkwardness when a young, naïve captain tries to make deals for agricultural machines.
All of the swearing in Warrior Cats is made up of either "mouse dung" (mild) or "fox dung" (more severe). "Mouse-brain" is a mild insult meaning "stupid" or "silly". A group of cats from the mountains uses "beetle-brain" instead.
The cats really don't seem to like foxes: "foxhearted" is apparently a heavy insult (based on the reactions when it's used), which makes the cat actually named Foxheart have an Unfortunate Name.
Toward the climax of Watership Down, Bigwig tells General Woundwort 'Silflay hraka, u embleer rah'—though one could argue it's rather more Getting Crap Past the Radar, since any reader who's been paying even marginal attention to the rabbit language can easily translate it as "Eat shit, you stinking prince". Quite the Crowning Moment of Awesome.
Even worse, the blasphemous "Embleer Frith!" note literarily: Stinking God; roughly equivalent to "goddammit"
The Wheel of Time has quite a few, most commonly used by Mat, including "Light", "Burn me", and "Blood and bloody ashes" (and once "may the Light burn me to blood and ashes if it is not so").
These curses are quite consistent with the philosophy and cultures depicted. One which was rather vulgar was "Mother's milk in a cup" (said by Elayne, who is noted to try to remember the courser language she hears).
One of the Forsaken does use a curse word, tsag, which another Forsaken finds strong, although it is meaningless to us.
When Mat's angry with someone, he might call them a "son of spavined goat". When he's really upset, he says "Sheep swallop and bloody buttered onions!" — a phrase that Elayne carefully memorizes.
In the Indian novel The White Tiger: Whenever Balram starts talking about his or someone else's 'beak'.
Un-Bowdlerising example: in Elinor Huntington's translation of Wind And Sparks one protagonist, a Muggle soldier of a magic war, keeps swearing "Screw a toad!" In the original Russian and in German translation it was milder(?) "Burst your toad!" that made even less sense.
In Hullo Russia Goodbye England, Flight-Lieutenant Silk has an affair with a former model who has dropped out of society to live a poor but content life in the country. The relationship occupies a sort of halfway house between a Friends with Benefits situation and outright prostitution. There is something genuine between them. But Silk uses the cover story of "taking cello lessons" to justify his visits to her cottage and the unspoken agreement is that the cello lessons cost him £5 a session. the fact the cello never leaves its case is immaterial. note Until Mrs silk challenges him to play a middle-C at the very least.
Journey to Chaos: Caffour complains about how no one has "yanked his banana" in many years.
In Empire Star by Samuel R. Delany, "Jhup" is an alternate term for plyasil, the sole export product of Comet Jo's home world of Rhys. It is also considered a strong obscentity—but only on Rhys. This leads to a discussion of the nature of obscene words after Jo apologizes for using the word to a spacer visiting Rhys.