postbag

A straightforward, crude slang term for a colostomy bag — a medical pouch attached externally to collect waste after certain surgeries that reroute the digestive tract. The term is typically used informally and sometimes dismissively by patients themselves or their close circles, functioning as dark humor around a sensitive medical reality. Less commonly, it may be used as a general insult, but the medical meaning is its primary documented sense.

British slang, primarily used in Scotland and Northern England, for a drug addict — particularly someone who uses heroin or other street drugs heavily. The bag element likely references the small bags in which drugs are sold or carried. Used without much sympathy in casual conversation but not always with pure contempt; context determines tone. Strongly associated with working-class urban environments.

(British, transitive, idiomatic, humorous, metonym) To attack verbally or subject to criticism (typically used of a woman).

(chiefly, UK, Irish, Commonwealth) A box into which mail is put.