What does bum mean?
Bum is a versatile informal word with sharply different meanings on opposite sides of the Atlantic. In North America it most often describes an idle or disreputable person — a loafer who lives off others, or historically a homeless vagrant — and as a verb it means to beg or borrow without repaying, as in 'to bum a cigarette'. It also works adjectivally to describe anything defective or unfair, as in 'a bum deal' or 'a bum leg'. In British English, by contrast, bum primarily denotes the buttocks, making it a mildly cheeky rather than insulting term. The word derives from an older verb meaning to loaf, appearing in American usage by the mid-nineteenth century. Its register is firmly informal: useful for casual conversation and vivid writing, but best avoided in formal contexts, where its slangy connotations of laziness or vulgarity may jar.
A lazy or idle person who avoids work and lives at the expense of others; also, a homeless vagrant.
"His uncle was known around town as a hopeless bum who never held a job for long."
Mildly derogatory in North American English.
The buttocks (chiefly British English).
"The toddler fell down and landed on her bum."
Informal and slightly childish in tone; the dominant meaning of 'bum' in British English.
To beg, borrow, or cadge something from another person without any intention of repaying.
"Can I bum a ride home from practice?"
Worthless, defective, or unfair; of poor quality.
"He complained that the referee made a bum call in the final minute."
Common in informal phrases such as 'bum deal', 'bum steer', and 'bum rap'.
Standard pluralization applies to both senses of the noun.
"The beach was crowded with sunburned bums lounging by the boardwalk."
In American English calling someone a 'bum' is an insult — but in British English 'bum' is just what you sit on.
Reviewed by Deb Chak, Editor. AI-assisted content curated by RJS Tech Solutions LLP.
Etymology of bum
The noun 'bum' in the sense of a lazy or dissolute person arose in American English in the mid-nineteenth century, likely from an earlier verb 'bum' meaning to loaf or idle, whose ultimate origin is uncertain. The British anatomical sense (buttocks) is attested somewhat later, in the nineteenth century. A separate nautical term, 'bumboat', denoting a small boat selling provisions to ships, shares the word's early form but is of independent origin.
Related word forms
How bum is actually used
'Bum' is informal throughout. In American English it is mildly derogatory when applied to people. In British English its dominant meaning is anatomical (the buttocks), which makes cross-register use risky: an innocent phrase in one dialect can be rude or confusing in the other. The adjective sense ('bum leg', 'bum steer') is common colloquially but avoided in formal writing.
Easily confused with bum
Bomb is an explosive device or an utter failure, whereas bum is a person who shirks work, the buttocks, or something of poor quality.
Dumb means unable to speak or stupid, whereas bum refers to a loafer, the buttocks, or something worthless.