Longman Dictionary of Contemporary English - ass

~ n 1 »PART OF BODY« especially AmE an impolite word for the part of your body that you sit on  (I tripped and fell flat on my ass.) 2 get your ass in gear also move your ass spoken an impolite way of telling someone to hurry  (Get your ass in gear, or you'll miss your plane!) 3 get off your ass AmE spoken an impolite way of telling someone to stop being lazy  (If you want to pass this test, you'd better get off your ass and study!) 4 kick/whip sb's ass also kick (some) ass AmE slang to beat someone easily in a fight, game, or sport  (Let's get out there and kick some ass.) 5 be on sb's ass AmE spoken a) an impolite way of saying that someone is annoying you by telling you to do things you do not want to do  (My boss is on my ass all the time.) b) an impolite way of saying that someone is driving very close to the back of another car 6 get your ass over here AmE spoken an impolite way of telling someone to come quickly 7 my ass! AmE spoken an impolite way of saying that you do not believe something  ("He said he ran twenty miles." "Twenty miles my ass!") 8 »STUPID PERSON« informal a stupid, annoying person  (make an ass of yourself (=do something stupid or embarrassing)) 9 sb doesn't know their ass from their elbow AmE spoken an impolite way of saying that someone is stupid 10 »ANIMAL« old use a donkey  (- see also arse1, haul ass haul1 (6), kiss sb's ass kiss1 (6), pain in the arse/ass etc pain1 (3), piece of ass piece1 (21), smart arse)