The "other half" of how nudism is portrayed in the media, used less often than the Innocent Fanservice Girl variation — ironic, due to this being technically speaking a more realistic approximation of nudist beliefs.
The key difference between a Shameless Fanservice Girl and an Innocent Fanservice Girl is that while the Innocent Fanservice Girl's lack of a nudity taboo is based on the fact that she never knew of its existence (i.e., she's too innocent to know better), the Shameless Fanservice Girl does know, but just doesn't care. She ignores nudity taboos by choice and couldn't care less who's disturbed by it.
This doesn't necessarily mean she prances around the streets in the nude 24/7. Perhaps she's just the type who sleeps in the nude, spends all of her private time in her house without clothing, or only goes nude when she feels safe doing so, such as at the beach. But whatever the reasoning and specifics, the key factor is that she does understand that nudity is typically frowned upon by people.
Her amount of consideration to people who are uncomfortable around her nudity can vary. Sometimes she will get dressed just for the sake of her house guests. Other times she'll have a "screw you" attitude and not let the disturbed countenance of her house guests persuade her to stop being naked if she wants to be. It pretty much depends on what kind of person she is.
Satirical or comedic versions frequently have her facing no repercussions at all (much like her innocent sister-trope), or only comedic ones. Sometimes, for extra comedic effect, her nudity will only be noticed by one person whilst being ignored by everyone else for no apparent reason. More serious portrayals will tend towards the discreet: Characters that reject the taboo but otherwise do not make it an issue, or only in semi-private situations where they are within their rights to decide what to wear.
While this trope can overlap with Attention Whores, it is not a subtrope. This is not "the exhibitionism trope", but rather, "the knowingly unashamed trope". This does not preclude a rare Attention Whore who is also a Shameless Fanservice Girl, but it is not a requirement. The polar opposite of Reluctant Fanservice Girl.
Mitsuka-sensei from DearS is this in spades, and even the horny male teenagers in her class are turned off by her (despite being very attractive aesthetically) because of how far she takes this trope. It also might have something to do with Mitsuka being what Japan calls a Christmas Cake, meaning over the age of 25, and thus automatically unappealing because they are "unmarriable". The series on occasion pokes fun of the concept.
Haruhi Suzumiya: The main female character, Haruhi, doesn't have a problem with changing in public because she doesn't care about anyone else or what they think. A major sign of her growing relationship with Kyon is that she doesbegin to care if he's watching and violently tsuns him out of the room.
Yoshinoya-sensei from Hidamari Sketch she always tells her students that she can model nude if they wanted.
Mio in Ano Natsu De Matteru is a deconstruction of this trope — having been raised as a nudist her whole life she was never raised with a nudity taboo. However, instead of having the standard effect on her personality it actually causes her a lot of self confidence problems — she's convinced that she's a weirdo in comparison to everyone else. She still doesn't wear clothing around the house, can't sleep with clothes on (even in group situations), and can't remember to wear underwear, but altogether she's humiliated by the fact that she's a "weird nudist" more than anything else. Ironically, or perhaps part of the deconstruction, she wears fairly conservative outfits for the most part (even going so far as to wear a hooded sweatshirt to the pool), and is the first anime and manga character on this list to actually call themselves a nudist, instead of just randomly deciding not to wear clothes when fanservice calls for it.
Erza Scarlet mentions in one episode that maybe she should walk around the guild naked. In a hotsprings scene, some of the girls are bathing when they realize the boys are spying on them. Erza's reaction is to let them in.
Natsu seems to be like this too. When he ends up naked along with his female guildmates in two different contexts (Lucy, Erza and Wendy at a hot spring and Lisanna in a prison), he has some rather amusing reactions about the fact that they are in the nude, but he doesn't seem to mind nor think about that they also get to see him naked.
Lucy Ashley, unlike Lucy Heartfilia, is a bit shameless and offers to let Natsu see her naked.
Rachel Stanley has no problem exposing herself more in order to gain more attention.
Shigure Kosaka. She does get pissed when Kensei Ma attempts to peek on her in the bath, but could care less about bathing with Kenichi, and doesn't even bother to lock the door to her room when she changes. However, when she's captured by YAMI and subjected to a Shameful Strip, she blushes and angrily calls them perverts.
Ranma is a bit of a downplayed version of this. He doesn't hate clothes; he just really doesn't care about whether he's naked or not. He's been known to go topless in front of men without batting an eyelid and has used his female form's good looks to tease men into giving him what he wants or needs. It's usually through Akane covering him up with clothes or a towel that he preserves any modesty. We also see him in male form at home in nothing but boxers quite a bit.
Shampoo acts this way when she's trying to seduce Ranma. She simply doesn't have any problem with showing up in his bathroom naked.
She was wearing only a shirt at one point and flipped the bottom up to make him blush shortly thereafter.
Then of course there is that wonderful hot spring scene, where Yoruichi strips, Ichigo protests, and when he looks she's a cat. After a few moments of conversing he looks back and she's still naked, but now human. This was specifically meant to make Ichigo flustered.
And then there was the time readers learn she actually came up with a way to Flash Step out of her clothes (she may be the master of the technique, but really?).
Around the time Isshin and Masaki met, he saw her naked. She just laughed and made fun of him for getting flustered.
Yuusaku in Toradora!. One episode featured him nonchalantly walking into a room, in full view of the three main girls, with nothing covering him except a handtowel. He excuses himself saying he didn't know there were women in the room, but couldn't be less ashamed.
In Battle Athletes (not to be confused with Battle Athletes Victory, the remake) Kris Christopher calmly parades around the room she shares with her teammates completely naked as it's part of her culture/religion. The other girls are not particularly thrilled about this.
Saori Shikikagami from Ladies Versus Butlers! sees no problem with stripping on any given occasion. Even if it's by accident, she still treats it as no big deal. Her sister Sanae tries to keep her under control, but it doesn't work very well.
Mami of Esper Mami is a strange variant — her father's a painter, and she works for him as a nude model. As a result, she has no hang ups about being nude, especially at home.
After Nanami gets stripped to a halter and shorts by a magic attack in Dog Days, she simply laughs, strikes a pose, and says "Showing this much is okay!" She does have a limit, however, as shown when a later attack strips her completely naked.
Ryuuko Kounuma from Wolf Guy - Wolfen Crest. Not only doesn't seem to mind being nude in front of Inugami, but also not so much about masturbating in his proximity.
Princess Hathor Nefert in Anatolia Story, who walks around topless like it's nothing much to the shock of the Hitite ladies and Yuri. Kinda justified: she's from the VERY hot Egypt, so she's used to taking off her top to be more comfortable when it's too sunny for her taste.note It's an Artistic License justification. In very hot countries, especially very sunny and dry ones, people normally stay covered all the time and put MORE clothing if it's particularly hot (as well as drink HOT drinks). As with cold and snow, imagining linear dependance between heat and clothing is a mistake.
Majority of Mamoru Onodera's Battle Harem in Deadline Summonner. Out of the ten cute monster girls, they are only three who are dressed in more than a few scraps of fabric. Justified in that they probably don't share the same perception of "decency" as humans.
Free!'s Haruka Nanase doesn't care if he's in public — if there's an opportunity for him to swim, he won't hesitate to strip down to his trunks.
Holo of Spice and Wolf has absolutely no problem with other people seeing her naked — her first conversation with Lawrence, famously, was conducted entirely with her completely nude, and he was much more unnerved than her. Justified, since she's actually a wolf — when she runs around all the time in her fur, why should she care if people see her human skin? She prefers to wear clothing most of the time, though, since it's much colder without her fur.
Played for Drama, as the price one must pay to wield the full power of a Kamui (a living uniform), apart from feeding it blood, is to appear half-naked while wearing it. Satsuki fully embraces it with neither shame nor hesitation to show her total mastery of its power, while Ryuko must overcome her fear of everyone gawking at her naked body in order to catch up. For Satsuki this is greatly aided by her thinking everyone else to be so beneath her that she doesn't even care what they see. Though in actuality, she do whatever it takes in order to accomplish her goals.
Reka in The Secret History is frequently naked and knows exactly what effect she has on men.
The title character in Lady S has absolutely no problem escaping a house in her underwear. She once had to climb a roof, and removed her dress because it wasn't practical, rather than tearing it.
In an issue of Batman and the Outsiders, Cassandra Cain moves in with Grace and Anissa, and gets a glass of orange juice while completely naked, simply because she doesn't bother. Grace remarks "I didn't know the Bat-crowd was clothing-optional", while Anissa observes "she has so many scars..."
Catman from Secret Six is a Rare Male Example, since he frequently winds up naked and knows why it makes people uncomfortable, he simply doesn't give a shit, which ties into his semi-feral personality.
In Wild Arms: The Dee Legacy, Anne Hardin simply has more important concerns than modesty, bathing and changing whenever she needs to, although she has a good deal of awareness when someone is paying more attention when necessary.
Films — Live-Action
A defining example of this trope in film is the nude biker (Gilda Texter) in Vanishing Point (1971).
Trash from Return of the Living Dead likes hanging out at graveyards naked, and the idea of asking anybody for something to wear does not occur to her for the rest of the movie. She does grab someone's vest when the Trioxin-tainted rain starts to fall, but in that case her concern is protection instead of modesty. She never does find any pants.
Mystique from the X-Men films does not give a damn about the implications of being naked all the time. It helps that her privates are naturally covered by blue scales and she probably doesn't feel the cold. It also helps that she can shapeshift the appearance of clothes onto herself when impersonating others, so actual clothing would be an impediment.
The actress playing Mystique wasn't wearing much more than blue paint and prosthetic appliques but she said she didn't feel at all naked - though she admitted she sure looked naked.
In the Tomb Raider movies, Lara is made out to be something of this. In the first film, Lara is offered a dress by her butler as she steps out of the shower. She tosses the towel she has wrapped around her aside in indignation, giving us a moment of Toplessness from the Back.
A bizarre twist on this trope occurs in Isaac Asimov's novel The Naked Sun. The Solarians, humans on a sparsely-populated colony world where they usually live alone on vast estates with thousands of robot servants, have become extreme misanthropes. They can barely tolerate physical proximity to other human beings. However, they make extensive use of telepresence videoconferencing ("viewing") to communicate. When Elijah Baley, a detective from Earth investigating a murder, first interviews the victim's wife it is via such means and she casually talks to him naked having just come out of her bath. Because he is only viewing her, not actually seeing her (i.e. in-person), she sees nothing wrong with being naked on a video call and is confused by Elijah's discomfort. However, like any other Solarian, she would find it extremely uncomfortable to be in the actual presence of another person, even if she were fully-clothed (although she is nowhere near as phobic about it as most of her people).
The infamous Australian soap opera Number 96 had Miss. Hemmingway, a compulsive nudist who was in therapy to try and cure her dysfunction. She often "appeared" in the lobby of the resident psychiatrist character's office.
Zhaan from Farscape belongs to a species with no nudity taboo. She does wear clothes most of the time, though it's used for Fanservice at least once. She knows exactly how other life forms are likely to react to her nudity. Including Squick in case of the non-humanoid Rygel.
Cameron from The Sarah Connor Chronicles. As a Terminator she's utterly nonchalant about how little she wears or who sees her. On the other hand she's acutely aware of the reactions others have to her body and is definitely not above using them.
There was a variation of this on Cheers, one who never appeared on screen. In a sub-plot to the season four finale, Norm mentioned how his wife's sister Donna, who he described as an "oversexed exhibitionist" was visiting, and how he was afraid she was flirting with him, describing how she was rather... liberal around him. (As it turned out, she was harmless.)
In Season 4 of The Vampire Diaries Elena displays this behaviour when she loses her humanity, walking completely naked in front of the Salvatore brothers and Caroline.
On Teen Wolf Malia doesn't care about Stiles walking in on her showering.
Naturally, just about everyone in Bally's Playboy pinball qualifies for this trope, with the sole exception of Hugh Hefner himself.
WWE Diva Miss Kitty, whose entire existence seemed to revolve around her desire to be naked. She did a nude scene at WrestleMania 2000, flashed the audience after she became Women's Champion and tried to combat Right to Censor with her own Right to Nudity.
More recently, Kelly Kelly, who began her time in WWE's revamped ECW as an exhibitionist — at age 19.
Amane from Grisaia No Kajitsu is this to a T, and her reactions to main protagonist Yuuji accidentally walking in on her naked tend to be nonchalance (she's more confused about Yuuji's nonchalance than vice versa). Subverted in one instance when Yuuji walks in on her while she's in his room, while she's clothed but about to engage in a... personal moment, which embarrasses her immensely.
Deliberately invoked with the Whites in Lucky Day Forever to show how inhuman they are in comparison to the Proles.
El Goonish Shive. Grace progresses from Innocent Fanservice Girl to this after realizing her preference for nudity has sexual connotations to most people. She still doesn't agree with humankind's nudity taboo, but can fake it well enough to get along with people.
Sarine from Errant Story has this attitude, though it doesn't come up very often given the setting. Jon ogles her while she bathes and she is clearly not embarrassed, though she is annoyed at the interruption.
Zeetha. After being accidentally stripped down to her very short leather bikini, she doesn't bother to search for clothes for dozens of pages.
Lucrezia. She removed her dress, just because she's more interested in looking at her new body than she is in modesty. At this point, she wears quite modest underwear, but someone else would be ashamed of being in these clothes in front of a guy. It's heavily implied in the novel that Lucrezia is actually going completely naked in those scenes, but that they could only "write" about that, not show it.
Ménage à 3 has Matt and Senna for male and transsexual variants of the trope. Both are professional lingerie models and hence required to have limited nudity taboos, but both of them are also habitual seducers who are happy to exploit their looks to the full. Matt is fairly good-natured about this, if a bit of a bastard in his love life, but Senna is melodramatically vain and catty. As the comic itself is relaxed about depicting nudity, both provide plenty of fanservice for the readers.
Cammi of Sandra on the Rocks doesn't seem to give a damn. She does enjoy winding her boss Zoé up, with gratuitous nudity as well as with her casual affair with Domenico, Zoé's ex-husband and the owner of the company. Apparently, she's just so good a chauffeur that her job is safe regardless.
Aisha from Slimy Thief. She's an elf and elves aren't ashamed of being seen nude. When her human friend Azamat accidentally walks in on her taking a steam bath she tells him she doesn't mind if he looks just as long as he stops staring at her so creepily.
This is the whole idea behind the Naked Vlog trend on YouTube.
Faun Reinaka of Tasakeru. Her whole species tends to be like this.
"Sunglasses" from the Creamsicle meme has an ambiguous black band around her chest which can be interpreted as a skimpy top or a censor bar. In the latter case, it suggests casual toplessness.
The nudist Campbell family from Family Guy somehow go nude in public without more serious repercussions than their son getting bullied. They either ignore or fail to notice how disconcerting Peter and Lois initially find their nudity, and since nobody asks them politely to get dressed, it's hard to tell which.
The cast of Futurama tend to bounce around this. In some episodes, public nudity is completely normal, while in others, you can be arrested for streaking. Hilariously, the most common offender is Professor Farnsworth.