What is the idiom that means same thing as bite your tongue?

There are a few idioms that mean the same thing as "bite your tongue", which is to refrain from speaking, often to avoid saying something hurtful or inappropriate. Here are a few:

* Hold your tongue: This is a very similar idiom that directly translates to "keep your mouth shut" and emphasizes the act of not speaking.

* Keep your mouth shut: This is a more direct and forceful idiom that implies silence is mandatory.

* Zip it: This is a more informal and playful idiom that suggests a quick and complete closure of the mouth.

* Button your lip: This is a slightly archaic idiom but still used occasionally, implying a need to be quiet and discreet.

* Keep it under your hat: This idiom emphasizes secrecy and the need to not share information.

* Swallow your words: This idiom implies a regretful silence after already speaking.

The best idiom to use depends on the context and the desired level of formality.