slacks

The part of anything that hangs loose, having no strain upon it.

“take in the slack”

A tidal marsh or shallow that periodically fills and drains.

To slacken.

To mitigate; to reduce the strength of.

To lose cohesion or solidity by a chemical combination with water; to slake.

“Lime slacks.”

A temporary speed restriction where track maintenance or engineering work is being carried out at a particular place.

A valley, or small, shallow dell.

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)