1. (British) the bottom, backside, buttocks. From the Middle English period to the end of the 18th century it was possible to use this word in English without offending respectable persons. By the 19th century it was considered rude, perhaps unsurprisingly, in that its suggested origin was in 'bom' or 'boom', an imitation of the sound of flatulence.

2. a tramp, down-and-out, wastrel. This sense of the word is probably unrelated to the previous one. It is a 19th-century shortening of 'bummer', meaning an idler or loafer, from the German Bummler, meaning a 'layabout' (derived from bum- meln, meaning 'to dangle, hang about').

'It kind of upsets me that they talk about him as if he's a hopeless bum.' (Recorded, Canadian teenage girl, Lon- don, April 1996)

See also on the bum

3a. sodomy or the opportunity thereof. A vulgarism used mainly by heterosexuals, referring to homosexual activity.

3b. an act of sexual intercourse. A heterosexual synonym for tail.