keep one's mouth shut
To be or stay silent. - A rude expression when used as a command.
Быть молчаливым; хранить молчание. Если используется как команда, то звучит грубостью.
When the crooks were captured by the police, their leader warned them to keep their mouths shut.
Charles began to tell Barry how to kick the ball, and Barry said angrily, "Keep your mouth shut!"
I tried hard to keep my mouth shut during the boring speech.
Мне с трудом удавалось молчать во время скучной лекции.