not open one's mouth

Idioms

Also, shut one's mouth;. Be silent, repress one's feelings or opinions, keep a secret. For example, Don't worry, I'm not going to open my mouth on this issue, or She promised not to say a word about it to anyone. Also see hold one's tongue; keep one's mouth shut.

Definitions and idiom definitions from Dictionary.com Unabridged, based on the Random House Unabridged Dictionary, © Random House, Inc. 2023