Fan Casting Leotard of Power in Sort by Tropes

A character fights in a skintight leotard or, more generally, a swimsuit-esque one piece. Pretty common as a Super Hero trope, especially during its Golden Age, where the costume originated as gymnasts' and circus performers' garb and since then it isn't always used for Fanservice (strongmen and wrestlers were as likely to wear it as acrobats, and so you'll still see the occasional hulking bruiser wearing it to show off their massive musculature).