button one's lip

Verb

idiomatic

(idiomatic) To remain silent, especially in order to keep a secret or to avoid saying something inappropriate.

Japanese Meaning

秘密を守るために黙る / 不適切な発言を避けるために口を閉ざす / 不要な情報を話さず沈黙を保つ

In sensitive meetings, it's often wise to button one's lip until more information is available.

機密性の高い会議では、詳しい情報が出るまで口をつぐむのが賢明なことが多い。

Sense（1）

(idiomatic) To remain silent, especially in order to keep a secret or to avoid saying something inappropriate.

buttons one's lip

（ present singular third-person ）

buttoning one's lip

（ participle present ）

buttoned one's lip

（ participle past ）

buttoned one's lip

（ past ）