ass 1 (?s)n. pl. ass·es (?s??z) 1. Any of several hoofed mammals of the genus Equus, resembling and closely related to the horses but having a smaller build and longer ears, and including the domesticated donkey.2. A foolish or stupid person.[Middle English asse, from Old English assa, perhaps a hypocoristic for Old English dialectal (Northumbrian) asal, ultimately (perhaps via a Celtic form akin to Old Irish asal) from Latin asinus; see asinine.]ass 2 (?s)n. pl. ass·es (?s??z) Vulgar Slang 1. a. The buttocks.b. The anus.2. Sexual intercourse.adj. or assed (?st) Used in combination with adjectives as an intensive: I don’t want to play your dumb-ass game. That is one crazy-ass idea.Idiom: have (one’s) head up (one’s) ass To behave in an ignorant or foolish manner.[Middle English ars, from Old English ears; see ors- in Indo-European roots.]American Heritage® Dictionary of the English Language, Fifth Edition. Copyright © 2016 by Houghton Mifflin Harcourt Publishing Company. Published by Houghton Mifflin Harcourt Publishing Company. All rights reserved.ass (æs) n1. (Animals) either of two perissodactyl mammals of the horse family (Equidae), Equus asinus (African wild ass) or E. hemionus (Asiatic wild ass). They are hardy and sure-footed, having longer ears than the horse. 2. (Animals) (not in technical use) the domesticated variety of the African wild ass; donkey3. a foolish or ridiculously pompous person4. not within an ass’s roar of informal Irish not close to obtaining, winning, etc: she wasn’t within an ass’s roar of it. [Old English assa, probably from Old Irish asan, from Latin asinus; related to Greek onos ass]ass (æs) n1. chiefly slang US and Canadian the buttocks2. chiefly slang US and Canadian the anus3. chiefly offensive slang US and Canadian sexual intercourse or a woman considered sexually (esp in the phrase piece of ass)4. cover one’s ass slang chiefly US and Canadian to take such action as one considers necessary to avoid censure, ridicule, etc at a later time[Old English ærs; see arse]Collins English Dictionary ? Complete and Unabridged, 12th Edition 2014 © HarperCollins Publishers 1991, 1994, 1998, 2000, 2003, 2006, 2007, 2009, 2011, 2014ass1 (æs) n. 1. Also called donkey. a long-eared, slow, surefooted domesticated mammal, Equus asinus, related to the horse, used chiefly as a beast of burden. 2. any wild species of the genus Equus, as the onager. 3. a stupid, foolish, or stubborn person. [before 1000; Middle English asse, Old English assa, probably fr. Old Irish asan