Similiar to Sus Ass Bitch; Sus Ass is a proper noun or title given to people when used to insult or name call.
Guy 1: Yo you got my weed
Guy 2: Uhhhh ( fumbles in pockets)

Guy 1: Yo quit being a Sus Ass
Guy 2 : Fuck you man ( runs away)

Later

Guy 1: Yo Greg didnt come through with the weed
Guy 3: Damn that fool IS a sus ass
by lijlover November 13, 2017
A professor or teacher who gives out food as prizes for answering a question.
Person #1: Professor Smith just gave me yogurt.
Person #2: What a Su Ass!
by sir fig newton October 16, 2019