let your hair down

let (one's) hair down

To cease acting formally or conservatively; to ignore or relinquish one's inhibitions or reservations. Also worded as "let down (one's) hair." Come on, Jim, this is a party! Let your hair down and go a little wild!
See also: down, hair, let

let your hair down

COMMON If you let your hair down, you relax and enjoy yourself, and do not worry about being dignified or behaving correctly. It is only with friends that most people feel they can let their hair down and be themselves. He enjoyed all the jokes, but you got the impression he couldn't really let his hair down.
See also: down, hair, let