一言不发
一言不发[yī yán bù fā]1.■not to utter a single word; be as silent as the grave; become almost as silent as a post; button up one's mouth; control one's tongue; have nothing to say for oneself; keep one's mouth shut; keep silent and say nothing; not to breathe a word (of); not to drop a word (of); not to say a word (about); say nothing
