Definitions
1.nounThe part of anything that hangs loose, having no strain upon it."take in the slack"
2.nounA tidal marsh or shallow that periodically fills and drains.
3.verbTo slacken.
4.verbTo mitigate; to reduce the strength of.
5.verbTo lose cohesion or solidity by a chemical combination with water; to slake."Lime slacks."
6.nounA temporary speed restriction where track maintenance or engineering work is being carried out at a particular place.
7.nounA valley, or small, shallow dell.
8.nounSemi-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)