Let one's hair down

1. to relax and enjoy yourself without worrying what other people will think

• It's nice to let your hair down once in a while and go a bit wild.

• The party gives you a chance to let your hair down at the end of the week.

2. Figurative: to tell [someone] everything; to tell one's innermost feelings and secrets.

• Let your hair down and tell me all about it. Come on. Let your hair down and tell me what you really think.

3. Lit. to undo one's hair and let it fall freely.

• When she took off her glasses and let her hair down, she was incredibly beautiful