1
to shut one's mouth;to hold one's tongue;to keep silent
usu. as 口を〜
See also:
口をつぐむ (くちをつぐむ)
彼は叱られているとき口をつぐんでいた。
He held his tongue while he was being scolded.
Other forms
鉗む 【つぐむ】 (rarely used kanji form)