Clothing Reflects Personality, and as that index's organisation suggests, one of the most pervasive categories of identity is gender. Men wear men's clothing. Women wear women's clothing. Nonbinary and androgynous characters, therefore, wear the secret third option: everything. Tautologically, gender-neutral clothing (if it exists in a given culture) can be worn by anyone without attracting attention. So if a character's gender nonconformity is important, a very visible way to get the audience's attention is to combine individual articles of clothing that are strongly gender-coded in conflicting directions.
This often involves gender stereotypes of various depths, and might itself be called a bigender stereotype. However, both costume design and gender norms are considerably more complicated than "women wear skirts, pink, and lipstick" vs "men wear jackets, blue, and pomade". Perhaps women wear light hues and delicate filigree while men wear neutral-toned colour blocks and rectilinear patterns, or men's clothing is rigid and angular but women's clothing is flowy or form-fitting. Whether someone's fashion sense is supposed to be "masculine" or "feminine" involves details of fabric, cut, pattern, colour scheme, and so on...which varies not only between cultures and settings but between social contexts in the same setting. What matters is what kinds of Gendered Outfits the rest of the cast are wearing — if frilly waistcoats are for boys, and shoulder sashes are for girls, then Cassidy stands out by wearing both. Whether the results are more aesthetic or motley depends on the character and the tone of the story.
In reality, of course, it's quite an assumption to expect people to fit their entire identity onto their literal sleeves. Nonbinary people look like everyone else, and anyone can decide to wear any style they want. The clothes don't care.
May be Otherworldly and Sexually Ambiguous, or part of a Masculine, Feminine, Androgyne Trio. Compare Camp Gay, with which this trope has a complicated historical relationship by way of Trans Equals Gay; breaking gendered fashion norms is a queer tradition. Can also be related to Eccentric Fashion Designer, Fashionable Asymmetry, The Fashionista, Quirky Girl, Quirky Tux, Recursive Crossdressing.
Examples:
- Momiji Sohma in Fruits Basket is In Touch with His Feminine Side and wears a girl's school uniform with shorts instead of a skirt. After he has a growth spurt and looks more masculine and handsome, he switches to the standard boy's uniform.
- Komi Can't Communicate: To comply with their school dress code, Osana Najimi wears the shirt, tie, and blazer from the boys' uniform, and the skirt, shoes, and stockings from the girls'. (This briefly confuses Tadano, as he hasn't seen them over the summer and remembers them presenting male last year, but he adjusts quickly after realising how much he doesn't know about them.) Osana refuses to elaborate on their gender and alternately claims to be either a boy or girl whenever they find it convenient or funny.
- Revolutionary Girl Utena: Utena's Custom Uniform is usually just called a "boy's school uniform", but only that's only accurate for the top. On bottom, she wears the shorts the girl's wear in gym.
- Welcome to Demon School! Iruma-kun: Back when they were a student at Babyls, Opera wore the female uniform top and the male uniform bottom.
- Doom Patrol: Grant Morrison portrayed Rebis exploring their metamorphosis (into an alchemical fusion of male, female, and energy spirit) through clothing - for example, adding pearls, briefs, and a lace bra
◊ to their customary full-body bandages and sunglasses.
- Runaways: In Runaways (Rainbow Rowell), after Xavin was retconned into being nonbinary, their fashion sense changed. They are now often depicted in a Majesdanian-style military outfit, but with a crop top and long, undercut hair.
- The Sandman (1989): Desire is neither entirely male nor entirely female, and thus sometimes they'll wear a fancy men's suit, and sometimes they'll wear a dress, and sometimes they'll wear a mix of the two. And, being Desire, sometimes they don't bother with clothing at all.
- Teen Titans: In Teen Titans Academy, Stitch is a sentient ragdoll brought to life by Dr. Fate, and thus doesn't really have a set gender. Consequently, they often wear a mix of masculine jackets, sweaters, and jerseys with a skirt.
- In A Series of Unfortunate Events (2004), Count Olaf's Henchperson of Indeterminate Gender wears half a wedding dress sewn to half a tuxedo to Olaf and Violet's wedding.
- A Wrinkle in Time (2018): The Happy Medium is a medium, who is "medium" in many aspects, including gender. Reflecting this, they wear a single-sleeve dress, balanced out by Manly Facial Hair.
- One of the limericks in Edward Gorey's The Listing Attic concerns the "Cousins" from Herts, whose "sex is in doubt / For they're never without / Their moustaches and long, trailing skirts". In Gorey's illustration they also have bowler hats, and the one with an upturned moustache has a tie while the one with the drooping moustache has a collar brooch.
- Laura Henderson in My Next Life as a Villainess: All Routes Lead to Doom! is a Medieval European Fantasy equivalent of a trans woman, but since her workplace requires wearing gendered uniforms (as one would expect from the Middle Ages) yet she's still considered a man by society, she wears a male uniform that puts in a lot of frills and ribbons on.
- Reign of the Seven Spellblades: Fourth-year Carlos Whitrow, who is AMAB non-binary, is depicted in the novel illustrations and the manga and anime adaptations as wearing a mix of gender-codings: they wear a men's school uniform modified with a lace choker, high-heeled ankle boots, and a rose boutonniere.
- Community: In one episode, Dean Pelton (whose exact sexuality and gender were never fully clarified, but who definitely isn't straight) wears an outfit literally split by gender down the middle◊.
- Glee:
- Discussed with Kurt Hummel, The Fashionista who once stated that "fashion has no gender" when someone commented that he was wearing what looked like a women's sweater. His style shifts between more Camp Gay masculine (i.e. bowties and suspenders) and more feminine throughout the series, and a couple of times, like in the Lady Gaga tribute "Theatricality", he wore a dress. However, in Season 3, he draws a line at wearing a dress onstage at Nationals.
- Trans woman Unique Adams first appears as a closeted boy whose feminine side is only for performing, so her style slowly shifts from more nerdy masculine to fully feminine across her appearances as she figures out her identity.
- The character Ian Wright in Quantum Leap (2022) is nonbinary, played by a nonbinary actor. Their clothing and accessories choices reflect a mix of masculine, feminine, and gender-neutral styles that vary over the years in which Ian appears.
- Star Trek: Strange New Worlds: In "The Serene Squall", Dr. Aspen (who is actually the Space Pirate captain "Angel"), played by non-binary actress Jesse James Keitel, uses "they/them" pronouns and wears an embroidered black bodystocking and combat boots. They have a couple significant conversations with Spock about his being a Half-Human Hybrid, suggesting he view being half-Vulcan, half-human as a point on a spectrum instead of trying to fully be one or the other.
- In an unofficial Animated Music Video for "Albuquerque" by "Weird Al" Yankovic, the Hermaphrodite who steals the protagonist's lucky snorkel is drawn as wearing an outfit with pants on one side and a skirt on the other.
- Characters Welcome: In "The Most Unpredictable Batman Villain Yet," the Barking Glass's whole shtick is making everything they are, say, and do as baffling and unpredictable as possible. This includes a garish outfit with a beanie hat, a long black and white wig, poorly smeared-on lipstick, convertible mittens, a crop top depicting Animal from The Muppets, and boating shorts. They claim to be bisexual and deliberately keep their gender ambiguous, singing a song that goes "My middle name is Grover and my middle name is Anne, what am I, am I a woman or a man?" Of course, they're also a Compulsive Liar, so who knows how true any of that is.
- Mother 3: The six Magypsies are genderless snail people based on gender nonconforming friends of Shigesato Itoi, resembling affectionate stereotypes of Camp Gay bearded drag queens. Most of their clothing leans heavily femme, but Doria dresses like a lavender leatherman with suspenders and heels, while Lydia looks more Shakespearean with a ruff or boa. They all guard the Seven Needles with their lives, and each one passes on a Tragic Keepsake to Lucas's party in the form of a razor paired with a tube of lipstick.
- El Goonish Shive: In order to help Susan protest the new uniform dress code, Tedd (already androgynous who later realizes he is gender fluid) comes to school in a uniform with the male pants and the female vest on, challenging why the vest is coded feminine in the first place.
- The Flintstones: In "Circus Business", one of the performers at Stanley Rollem's carnival is Mr. His-'n'-Hers, a person who's literally half male, half female. Accordingly, they wear an outfit that's a suit on the male half and a dress on the female half.
- The Owl House: Luz wears a tuxedo with a poofy ballerina skirt to Grom. Overlaps with Gender Non Conforming Equals Gay, as this episode also officially confirms her relationship with female love interest Amity.
- Steven Universe:
- Crystal gems are feminine, but genderless; at their wedding ceremony, Sapphire wears a tuxedo, while the more butch Ruby wears a white bridal gown. After their vows, they fuse into Garnet, who forms joyfully wearing a combination of both.
- Main character Steven is a cisgender boy who carries his mother Rose Quartz's gemstone, allowing him to fuse with others. Since the majority of the other characters on the show are either explicitly female or, as described above, the genderless-but-feminine Gems, most of Steven's fusions (which are canonically nonbinary) wear a mix of whatever clothing the two components have on at the time of the act. For example, Stevonnie—Steven and his human friend Connie—wears Steven's trademark star T-shirt as a crop top underneath a blue sleeveless blouse and form-fitting jeans, while Rainbow Quartz 2.0—Steven and Pearl—has Pearl's powder-blue women's jacket and ballet slipper-like shoes combined with Steven's star shirt (again as a crop top) and jeans.
