Ass: Meaning, Buttocks Slang, Sexual Usage, and Consent
Ass is informal slang for the buttocks and may also refer to a donkey, a foolish person, sexual attraction, or anal activity depending on context.
Butt: Meaning, Anatomy, Slang, and Sexual Context
Butt is an informal word for the buttocks, the rounded parts at the back of the body that support movement, sitting, and sexual sensation.