Adjective. Used to describe someone or something that is attractive. Does not have to refer to the back end of the object, simply to the way they appear. Can also be used with suitable prosodic features to be sarcastic.
''That's one sexy ass guy''
by Hannah Watts November 03, 2006
1. A humorous exclamation uttered whilst playing a game, and while playing, the game characters unintentionally do something suggestive, for example, when playing Star Wars Battlefront, and you use the crawl feature and make the character back up, causing them to crawl backwards with their ass in the air. At that point, it is prudent to say "Sexy Ass!" to provide comical relief.
by aka_Pyro May 11, 2007