BUM

Bum is a multi-sense English term with several distinct meanings, depending on regional usage. The most common senses are informal terms for the buttocks and for a person who is homeless or idle. The word can also function as a verb, meaning to borrow, beg, or travel without a fixed purpose. The tone is casual and often colloquial.

As a noun for anatomy, bum refers to the fleshy region of the posterior. It is non-technical and widely understood in everyday speech. In many varieties of English, it is interchangeable with buttocks or backside, though buttocks is more formal and butt is more common in American English.

As a noun for a person, bum can denote a vagrant or a lazy, disreputable individual, especially in British English. While widely understood, the term can be insulting when applied to a real person, and it is considered crude or stigmatizing in formal contexts. Caution is advised when discussing homelessness or poverty.

As a verb, bum means to borrow or obtain something by asking, often without paying, as in "bum a cigarette" or "bum a ride." It can also mean to wander or lounge about, as in "bum around the city." The phrase "bum rap" denotes an unfair accusation, while "bum deal" describes an unfavorable arrangement.

Origins of the different senses are distinct and generally unclear; the anatomical sense is long-standing, while the vagrant sense emerged in British English in earlier centuries.