I. noun
Etymology: Middle English, from Old English assa, probably from Old Irish asan, from Latin asinus Date: before 12th century any of several hardy gregarious African or Asian perissodactyl mammals (genus Equus ) smaller than the horse and having long ears, a stupid, obstinate, or perverse person ,
II. noun or arse
Etymology: Middle English ars, ers, from Old English ærs, ears; akin to Old High German & Old Norse ars buttocks, Greek orrhos buttocks, oura tail Date: before 12th century
1. buttocks, anus , sexual intercourse ,
III. adverb
Etymology: 2ass
Date: circa 1920
often vulgar — used as a postpositive intensive especially with words of derogatory implication