Suffix added to adjectives and participles to intensify their meaning. By extention, these words may used as abstract nouns.
Party Grrl One: That stupid drunk-ass just fell into the pool!
Party Grrl Two: Hey, check out that nasty-ass drunk streaking down the street like a dumbass!
Party Grrl One: Cool! That gives me a chance to talk to his fineass brother.
-ass is a term to be added on to the end of a noun to turn it into an adjective. Is used primarily when the word the adjective applies to or the adjective itself is profane.
An augmentative suffix that can be added to short adjectives, generally of Germanic origin, usually requiring hyphenation, to form a stronger adjective.