bite one's tongue
Definition from Wiktionary, the free dictionary
- (idiomatic) To forcibly prevent oneself from speaking, especially in order to avoid saying something inappropriate or likely to cause a dispute.
- After the biting, bigoted comments she made about homosexuals, I wanted to scream at her, but I bit my tongue instead.
- Bite your tongue! She has enough on her mind without having to worry about comments like that from you.