- plural of
slacks pl (plural only, attributive slack)
- (dated) Semi-formal trousers which are less formal than those that are part of a suit but nowadays are considered suitable casualwear in most offices. (Takes a plural verb even when referring to a single pair; may be referred to as a pair of slacks.)
- 1941, Agatha Christie, N or M?:
- Discipline, that’s what we need. Discipline. How are we going to win the war without discipline? Do you know, sir, some of these fellows come on parade in slacks - so I’ve been told. Can’t expect to win a war that way. Slacks! My God!
The term is old-fashioned and now used mostly by older people and as applied primarily to women's trousers within traditional quarters of the U.S. clothing industry. (The term was never common in British English.) Despite being no longer considered leisurewear, they are still defined as casual trousers by all major American and British dictionaries.