bum [LME] There are two different words spelled bum. To the British, the bum is their bottom. The origin of this word is unknown, but the fact that many words suggesting roundness start bu- may be relevant. From the Middle Ages until around the 18th century bum in this sense was not regarded as a rude word: Shakespeare used it, and a treatise on surgery could refer to ‘[pulling] the feathers from the bums of hens or cocks’. The American bum [M19th] is a tramp or vagrant. The origin of this one is known—it is probably from bum [M19th] ‘to loaf, hang around’, which in turn is probably from bummer [M19th], which now chiefly means ‘a disappointing or unpleasant situation’ but in the USA first referred to a vagrant. It probably comes from German Bummler ‘unemployed person, vagrant’. The British slang word bumf [L19th], meaning ‘tedious printed material’ was originally bum fodder [M17th]—it first meant ‘toilet paper’.