behind closed doors

English

(idiomatic) In private; in one's private life; lacking (normal) public disclosure, in camera.
Synonyms: closed door, with closed doors

What you do with your girlfriend behind closed doors is none of my business.
- 2018 January 25, Amelia Gentleman, “Men-only clubs and menace: how the establishment maintains male power”, in the Guardian‎^[1]:
  A brilliant piece of undercover reporting revealed extraordinary details of how senior City executives behave behind closed doors.
- 2021 December 29, Nigel Harris, “Comment: Problems galore in 2021...”, in RAIL, number 947, page 3:
  A major problem has been the making of bad decisions behind closed doors.
(idiomatic, sports) Without public spectators.
Libya's opening home match in the World Cup qualifiers against Cameroon will be played at a neutral venue and behind closed doors, FIFA said on Friday. [2]
(idiomatic) stored in a hidden place.
- 2015 May 18, Angus Chen, How We Store Food At Home Could Be Linked To How Much We Eat:
  In other research, scientists have found that people who kept cereal out in the open were often about 20 pounds heavier than people who kept cereal behind closed doors.

in private