Sekirov Dictionary

keep one's mouth shut

verb1

•
To keep a secret; to refrain from speaking indiscreetly or carelessly; broadly, to refrain from speaking altogether.
- He thought that he could get him a regular salary if he would come to Packingtown and do as he was told, and keep his mouth shut. — 1905

forms

kept one's mouth shut · keeping one's mouth shut · keeps one's mouth shut

This dictionary works without the internet: on your phone · in Chrome