Bigass

a combining form of ass in the sense of ‘stupid person’ or ‘the buttocks’, used in slang words as an intensifier or with disparaging intent: big-ass; stupid-ass.
adj.

Pretentiously large: Abraham opened the door of his bigass Cadillac
Pretentious; self-important: his goddam big-ass face

used to form adjectives
Having buttocks of the specified sort: big-ass/ fatassed
used to form adjectives and nouns 2 Having a specified character or nature to a high degree: badass/ wildassed/ silly-ass