Not quite evil. Or at least, not enough for the audience to worry too much. The essence of this prop is evil in a camp sort of way, often bordering on 'dark' but safe fetishism. This often just means cooler and sexier costumes, and slightly more aggressive characters. Especially handy if you prefer a Dark Prince to a Good Prince.
Occasionally, Fashionable Evil occurs because Generic Cuteness permeates the entire setting, like a ghostly hell dimension suffused with fluffy purple things and Cute Monster Girls instead of actual monsters. The setting also supplies its own Anti Heroes, and since evil is the Informed Ability, these characters can be antagonistic if not outright malicious when needed.
Usually not the result of Villain Decay, as their popularity is predicted, especially if the story itself uses a non- Big Bad centered conflict. Contrast and compare Dark Is Not Evil and Putting on the Reich. The opposite is, of course, Fashion-Victim Villain.
Examples:
Anime
- One Piece: Be damned if those Marine Admirals don't look sharp in those suits. The pirates also can look sharp if they wanted to, just look at Sir Crocodile.
Fan Works
- Lelouch of the Wings of Rebellion: Black Mask's Thief Suit looks like a period outfit for the nobility, but with some concession to practicability like combat boots.
Films — Live-Action
- The Adventures of Pinocchio: All the villains are dressed in expensive clothes.
Literature
- The Land of Stories: Ezmia may be evil, but dang, the girl knows how to dress.
Live-Action TV
- Andor: The Empire fetishising Syril Karn is very particular about his uniforms, getting them tailored and acting like he's in the military despite starting out as a rent-a-cop who quickly gets fired for his gross incompetence. He keeps doing this even after he ends up in a Soul-Crushing Desk Job.
Western Animation
- My Life as a Teenage Robot: Brit and Tiff may be a pair of obnoxious Alpha Bitches, but there's no denying their fashion game is on point.
