緘ㄐㄧㄢjiān口ㄎㄡˇkǒu不ㄅㄨˋbù言ㄧㄢˊyán

閉口不說話。《明史·卷一八九·何遵傳》：「正德間，給事、御史挾勢凌人，趨權擇便，凡朝廷大闕失，群臣大奸惡，緘口不言。」似緘舌閉口、守口如瓶

英lips sealed and not saying anything (idiom); fig. to omit mention (of a non-person or embarrassing topic), to censor