- (dated) (plural only) Semi-formal trousers that are less formal than those part of a suit but suitable for wearing in most offices and therefore nowadays no longer considered casual trousers. (Takes a plural verb even when referring to a single pair; may be referred to as a pair of slacks)
- plural of
The term is old-fashioned and now used only by older people and by the clothing industry in the USA. (It was never common in British English.) Despite being no longer considered casual clothing, they are incorrectly still defined as casual trousers by all major American and British dictionaries.
- Third-person singular simple present indicative form of slack