let (one's) 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
Farlex Dictionary of Idioms.

let one's hair down

 
1. 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.
2. Fig. 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.
See also: down, hair, let
McGraw-Hill Dictionary of American Idioms and Phrasal Verbs.

let one's hair down

Also, let down one's hair. Drop one's reserve or inhibitions, behave casually or informally, as in Whenever the two sisters get together, they let their hair down and discuss all their problems . This expression alludes to the practice of women taking down their pinned-up long hair only in the privacy of the bedroom. [c. 1900]
See also: down, hair, let
The American Heritage® Dictionary of Idioms by Christine Ammer.

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
Collins COBUILD Idioms Dictionary, 3rd ed.

let your hair down

behave wildly or uninhibitedly. informal
See also: down, hair, let
Farlex Partner Idioms Dictionary

let your ˈhair down

(informal) relax completely and enjoy yourself, especially after a period when you have not been able to do so: Why don’t you let your hair down a bit? Come out with us for the evening.In the past, women wore their hair tied up when they were in public and only untied their hair in private or in informal situations.
See also: down, hair, let
Farlex Partner Idioms Dictionary

let (one's) hair down

To drop one's reserve or inhibitions.
See also: down, hair, let
American Heritage® Dictionary of the English Language, Fifth Edition.
See also:
  • let hair down
  • let one's hair down
  • let your hair down
  • let down (one's) hair
  • let one's hair down, to
  • part with
  • part with (someone or something)
  • give up the fight
  • give up the struggle
  • cancel out of (something)