三缄其口的英文：
[Literal Meaning]
three/seal/one's/mouth
absolute refusal to talk with one's mouth sealed more than once

[解释]
缄：封。在嘴上贴了三张封条。形容说话谨慎，现在也用来形容不肯或不敢开口。

[Explanation]
to speak with caution; to remain silent

[例子]
对于公司里的是非，他都三缄其口，不愿意发表任何看法。

[Example]
For the disputes in the company, he remained silent, not willing to make any comments.

[英文等价词]
to keep something to oneself

It is a time for people either to criticize helpfully or to hold their tongues
现在要提只能提积极意见，否则最好三缄其口。