expression, godan verb (-mu)
be careful in speech; watch one's words
Used when someone restrains their words, avoids saying something inappropriate, or speaks cautiously. Often used in admonitions or self-reflection.
上司の前では口を慎んだほうがいい。
You should watch your words in front of the boss.
彼は怒りを感じたが、口を慎
He felt angry but held his tongue.