The aversion and occasional subversion of Wouldn't Hit a Girl: a guy (good or evil) has no problems with violence against women. If he's good, it's either because he's just not sexist and he believes in beating people up equally, or because he knows that holding back against female opponents is a good way to get his ass kicked or killed or endanger his friends and allies. In earlier works, a male character would make up the point of "you're no lady" if the female in question has previously attacked him first (mostly female antagonists), in which case he will be allowed to attack. If he's evil, it's because... well, he's evil.
Of course, more modern female characters tend to go into battle fully expecting to be hit. If anything, many of them would probably be insulted if a male opponent went easy on them because of their gender.
In terms of censorship and editing on TV, any scene of male physical violence on females sometimes vary, including flashes, cutaways, or even trimming or cutting out the scene all together, to maintain a tasteful image.
In unedited works, you tend to see this more often than its inversion simply because times have changed, and society as a whole is taking the attitude that women aren't inferior in anything.
When hitting girls is Played for Laughs it can be a case of Slapstick Knows no Gender. Obviously not present when a woman hits a woman; then it's Designated Girl Fight.
When used as a video game genre, it's known as Ryona.
Dwight McCarthy from Sin City, though he's quite violently protective of them, has no problems with hitting or shooting a woman. Marv is usually the type that Wouldn't Hit a Girl, but he'll do it if he has to such as punching out Wendy, Goldie's sister, in order to spare her from watching him torture Goldie's killer, Kevin, to death, or mercilessly executing a madam who has taken to exploiting underage girls (in Silent Night).
Edward Blake in Watchmen hits women. And then tries to rape them. He may even kill a woman that he left pregnant. Ozymandias also kicks people in the stomach when they try to shoot him. Schoolboy heroics are redundant in his new world.
The Incredible Hulk has no qualms with your gender at all. If you've wronged him or pissed him off, you are to be smashed. Hence, Moonstone, Vapor, Mercy and Animus are treated accordingly.
The Mighty Thor may be a god, but he does not treat kindly to females that have went against him, lovers or not, as Hela and the Enchantress have found out.
In Ultimate Spider-Man, Spidey beats up a mother-daughter team of mutants who rob banks with their powers. Even the fact that the daughter was a little kid (a potty-mouthed, exploding-powers enabled extremely dangerous little kid) didn't stop him from beating them both up and handing them over to the cops. Later in issue 8, Spidey, Human Torch, Iceman, and the newly empowered Rick Jones encounter a quintet of lizard/girl hybrids stealing items from the Pegasus facility and don't even think twice about attacking them head-on, including full punches to the face. Although Johnny does keep trying to get that Lizard girl's phone number...
Poison Ivy also found this out the hard way against Batman. Knowing that he was reluctant to strike her, Ivy dealt Batman a No-Holds-Barred Beatdown until she had him pinned to the ground. She then urged him to kiss her - which, this being Poison Ivy we're talking about, would be immediately fatal - and taunted that there was no use resisting, because "I know you don't want to hit a woman." Batman confessed that, yes, that was true - but it wasn't going to stop him, and so he knocked Ivy unconscious with a single head-butt.
Cassidy has a history of striking women. This is not excused at all and is treated as an absolutely unforgivable sin. When Jesse discovers this, it fully cements Cassidy's Face-Heel Turn.
In Starr's first appearance, he is instructing an anti-terrorist unit. He is introduced as saying to always kill the women first, as the female terrorists they encounter will invariably be far more competent and dangerous than the men.
In an issue of Young Justice, students from an all-girls school held down Red Tornado's adopted daughter (and former heroine Arrowette, who tried to intervene) and cut off some of the girl's hair. Superboy knocked the whole crowd down with the sonic boom of his landing and then threatened to break backs and/or jaws if they didn't back off and shut up.
In the French comic Alpha, after heavily insulting him, the acting director of the CIA ask Alpha if he would hit a woman. He answers that she shouldn't talk about sex equality right now.
A terrorist once said to Captain America, "Patriotic fool — you would not hit a lady!" He decked her while saying, "Lady, you're no lady!"
Poopdeck Pappy slugged Olive Oyl when they first met. Olive never forgave him for it and the two have been at odds ever since.
Sure there's that, but The Joker's relationship with Harley has always been one of Domestic Abuse. And he's hurt plenty of women. Barbara Gordan comes to mind.
The Batman: Arkham City tie-in comic, has a paranoid Jenna Duffy lash out at Batman when she believes he's following her; he swiftly ends the match with a head-butt.
Lampshaded in "Ambush Bug", but then he is a) Ambush Bug and b) no hero anyway.
In Av X, Hawkeye does a brutal one to Magma. He's held in a prison and she brings him dinner. Suddenly Clint starts yelling out that there's glass in his baked potato and he's cut himself really bad. Amara doesn't believe it, but she's a bit on edge and so she peeks through the open food slot to see if he's okay. For that she gets a metal tray tossed into her throat and while she's keeling over, Clint grabs Amara's arm and pulls it through the slot. He then threatens to break her arm if she doesn't open the door. When she refuses, he goes through with it and breaks her arm, threatening to keep working her over until he does. Luckily another X-Man is nearby and knocks Clint off of her. As punishment, Clint and other escapees are put in a Virtual World that keeps replaying them trying to escape and failing.
In the 2007 Union Jack miniseries, the titular hero clocks Ecstasy after depowering her. He had to step over a lot of bodies to get to her.
Ashton from New World is a borderline psychopath who thinks he has the right to treat people under his station like tools for his pleasure and has no problem with savagely attacking Maddie when she rejects his advances.
In Action Pack Kira has no qualms about fighting women as seen by how he electrocutes Snapdragon and fights Quake. He even tells Naruto that you can't hold back on the enemy just because their women or you end up dead.
In Ponyfall: Rainbows, Cody has little hesitation about hitting the humanised Rainbow Dash in self-defence, to the point of knocking her unconscious. Garrett, from Ponyfall: Mile High Apple Pie, calls him out on it later.
Sleepwalker has a few female enemies, and he has no compunctions about giving them the exact same treatment he does to his male enemies.
TD of The Non-Bronyverse has no problems with hitting Celestia, though this does come right after she inadvertently traps him in Equestria. He does it a few more times throughout the various stories, but is well aware that as a Physical God he can't harm her in the slightest.
In Veritas, Gangryong WILL hit a girl or at least tries to, if she pisses him off.
Jin-Ho Myung, the protagonist of the manhwa, Unbalance × Unbalance. He has no objections to hitting a girl, and will in fact beat the crap out of them should it be provoked (which it was in one occasion). He even rants about the double standard of not hitting girls.
The music video for Garth Brooks' "The Thunder Rolls" includes a graphic domestic violence scene, where a young family man — returning home after a rendevous with a stripper at a local hotel — is confronted by his wife about where he's been. When he realizes she knows he's been cheating on her, he beats her senseless. (Most of the actual strikes take place in between lightning strikes, as the house loses power just as he loses patience with his wife.) When the man sees that his daughter has been awakened by the commotion and begs her daddy to stop beating mommy, he begins to go after her ... until she grabs her gun and shoots him dead.
Brooks — who in addition to performing the song onstage with his band as omniscient observers, plays the wife-beating, philandering husband in the action scenes — used the "wife-beating" scenes as a response to Capitol Records' reluctance to include the song's third verse (with the domestic violence themes) in the studio recording. Brooks would later peform the song with the "wife beating" third verse in concert. Critics and many others (including women's advocates) have given virtually unanimous praise to the video and the full version of the song as a powerful statement about the prevalence of male-on-female domestic violence, and it would win the Country Music Association's Video of the Year award in 1991.
"Independence Day" by Martina McBride. Like "The Thunder Rolls," the video to "Independence Day" contains graphic depictions of a drunken husband beating up his wife (for questioning his behavior), said scenes being intertwined with clips from a Fourth of July parade where two clowns engage in comic mock fighting. The lyrics are also quite frank ("She tried to pretend he wasn't drinkin' again/but daddy left the proof on her cheek").
Much like "The Thunder Rolls," "Independence Day" (both the video and song) won universal acclaim for its statement against domestic violence.
"Gunpowder & Lead" by Miranda Lambert — the lyrics in the song indicate that the female main character was physically abused by her much-larger boyfriend (Slapped my face and shook me like a rag doll); the brute was sent to prison as a result. (Just like "The Thunder Rolls" and "Independence Day," the song ends with a death — this time, of the antagonist, as the woman is standing ready to greet her bloodthirsty ex-boyfriend with a gun.)
Never Again by Nickelback from their third album was supposed to have a music video but their record label put a stop to it, due to the violent nature of the lyrics.
He's drunk again, it's time to fight
She must have done something wrong tonight
The living room becomes a boxing ring
It's time to run when you see him
Clenching his hands
She's just a woman
Funky Winkerbean: Averted — barely — in the ongoing 2013 storyline centering on Frankie Pierce (Lisa's one-time boyfriend) as he returns to Westview to cause trouble for Lisa's family and friends. An informant tells Les and Darin (Frankie's biological son) of a confrontation between Frankie and Lisa. One of the panels showed Frankie raising his fist and preparing to swing at Lisa (who is also wearing glasses), before a passerby (the informant) and his girlfriend run Frankie off.
One early Garfield strip featured Garfield inviting a female cat over for dinner after he falls in love with her. She then starts eating from his bowl. This makes him angry and he punches her sending her flying sky high.
A Sunday Peanuts strip has Lucy challenging Charlie Brown to fight - she'd done it before, leaving him slinking away and humiliated, but this time he was so annoyed he gave her the smallest tap on the nose. She naturally run off yelling that he'd hit a girl.
The Legend of the Five Rings rulebook explicitly mentions that Rokugan has far less rigid gender roles as Japan- it's entirely acceptable for women to be bushi, fight on the front lines, duel for their honour and so on.
Anyone engaging in Close Combat with the Sisters of Battle in Warhammer 40,000, Eldar Banshees, or Dark Eldar Wyches.
The stage adaptation of "Oliver Twist," called Oliver! features the abusive behavior of Bill Sikes toward his girlfriend, Nancy. Throughout the play, Nancy is a punching bag and the beatings grow progressively worse. In the end, Nancy tries to leave with Oliver, but Bill follows them and confronts them by London Bridge. Oliver tries to stop Bill from trying to grab Nancy, but is unsuccessful; Bill – in an unprecedented display of barbaric savagery – brutally clubs Nancy to death (in the original stage play; she has also been strangled, stabbed and/or had her throat slit). Bill takes Oliver hostage and uses the lad as a bargaining tool to ensure his freedom, but Bill is still caught and killed.
In The Moon Is Blue, David says that his wife divorced him for extreme cruelty after he hit her across the behind with a skillet. "Matter of fact, I rarely strike anyone but a woman," he explains.
A rather horrific variation of this occurs in Florida's version of Revenge of the Mummy, when Imhotep disintegrates a female ride operator into a skeleton.
Kaine in A Profile at one point assumes that Masayuki refuses to hit girls. He's very wrong, as is proved approximately five seconds later. It's not that he doesn't hit girls, he just never felt like hitting the girl in question until then.
The protagonist of Dra Koi gets in a fight with the dragon early on, at which point he apparently blows a hole through her neck and goes home. She shows up the next day in love with him.
Max is probably the only one who Wouldn't Hit a Girl in Precocious, and that's more from not wanting to hit anyone. The rest? An early strip shows one detail of the Big Ball of Violence as Bud popping Autumn in the jaw with an uppercut. Even the beauty pageant queen Dionne will dive in when sufficiently angered.
Danced around in Gunnerkrigg Court once; in an earlyish storyline, Eglamore says he doesn't want to fight Jones, even just as a quick demonstration for some students. Antimony gives him a Look and asks if it's because Jones is A Woman. "No, because in an enclosed space like this, Jones would wipe the floor with me." Note the implication that he'd be totally down with it if they were outside.
Almost all the evil guys in Union of Heroes: Manero, Ahres and The Wittener.
In Yet Another Fantasy Gamer Comic, Yapp the gnoll boy punches a troll girl who boasts about how women rule the mountain. "Women may rule, but braggarts always go down."
In The Order of the Stick,Roy is perfectly willing to fight Sabine. When she tries to seduce him, saying that he can do "anything" he wants to her, the next panel shows her flying out a window.
A straighter example is Tarquin casually snapping Haley's arm - in her case, she's a mortal female.
Goes without saying in Homestuck, which manages to be remarkably equal gender-wise. For example, in Act 6 at one point Jake decides that Meenah is basically fish Hitler and decides to beat her up, because that's what you do when you go back in time and meet Hitler. Of all the many, many problems with this idea, the fact that he's hitting a girl never even seems to occur to anyone. (For what it's worth, Meenah was so blinded by awe over her genocidal alternate counterpart that she barely noticed.)
Morris of Domain Tnemrot is perfectly willing to not only set his female slaves' hair on fire, he sucker punches children.
In Nodwick, striking Piffany (by anyone, male or female) is considered an Act of Ultimate Evil, but there are a few villains who have been vile enough to do it; this always brings down the wrath of the other three protagonists on said villain, and often that of the Powers That Be themselves.
Implied but not shown in Modern Day Treasure Seekers. Sam tells Cade that she was "knocked out" by the bad guys, but doesn't specify whether it was physical.
Wash of Red vs. Blue has absolutely no problem with hitting a girl if it's necessary. Or shooting one in the face. In both cases, however, the women he's fighting are also Freelancers (so very skilled, very dangerous fighters), and in one case, she's undeniably a better fighter than him anyway. And also not technically human.
After a crossover review of the Asylum's Sherlock Holmes, The Cinema Snob punched Obscurus Lupa in the face when she asked him if he wanted to watch another movie with her. An after the credits outtake shows Brad accidentally not pulling his punch, and hitting Lupa in the face; causing him to immediately start apologizing profusely.
Phase of the Whateley Universe. He doesn't like hitting people, but he has no qualms about hitting a girl if he needs to, because there are lots of girls who are far stronger than he is, including some of his team.
Described in great detail in Unforgivable. The character, Ricky, is a misogynist and extremely violent towards men and women.
In The Fate Of Paul Twister, when Paul discovers that Princess Ashley de Morgan was actually not the princess, but an impostor, he doesn't actually hit her, but he does put her in a choke hold and threaten severe violence against her, because she was almost certainly putting him in serious danger.
Chris Brown infamously beat Rihanna, cut an apology song or two, then wrote a song ("Deuces") about how an unnamed ex-girlfriend brought a ton of drama into his life and made him miserable, compares her to a vulture, and talks about how women lie, etc.
True for all wars that involve female combatants.
Or female non-combatants, for that matter.
Numerous ex-boyfriends of perpetually troubled country music star Mindy McCready.
Some parents have realized the dangers of teaching their sons to never hit a woman even in self-defense, and have so taught their sons to not hit women unless they are doing so in self-defense.
During the infamous "HLA segment" in WWE, Jamal of 3 Minute Warning decided to stiffnote wrestling slang that means to not pull your punches and hit/kick/slam the other person very hard one of the two girls in the segment, injuring her ribs and back.