1. a often vulgar; Buttocks — often used in emphatic reference to a specific person b often vulgar; anus
2. usually vulgar; sexual intercourse

ETYM Old Eng. asse, AS. assa; akin to Icel. asni, W. asen, asyn, Latin asinus, dim. aselus, Greek; also to AS. esol, Old High Germ. esil, German esel, Goth. asilus, Dan. aesel, Lith. asilas, Bohem. osel, Pol. osiel. Related to Ease.
(Irregular plural: asses).
Hardy and sure-footed animal smaller and with longer ears than the horse.
Any of several horselike, odd-toed, hoofed mammals of the genus Equus, family Equidae. Species include the African wild ass E. asinus, and the Asian wild ass E. hemionus. They differ from horses in their smaller size, larger ears, tufted tail, and characteristic bray. Donkeys and burros are domesticated asses.

A pompous fool.
Sometimes vulgar; a stupid, obstinate, or perverse person — often compounded with a preceding adjective

Often vulgar — used as a postpositive intensive especially with words of derogatory implication