not open (one's) mouth

(redirected from won't open their mouths)

not open (one's) mouth

To be completely silent; to remain discreet (about something); to not tell anyone (about something). All the while our teacher was shouting at us, we didn't open our mouths. Don't open your mouth about this! I would die of embarrassment if anyone were to find out.
See also: mouth, not, open

not open one's mouth

 and not utter a word
Fig. not to say anything at all; not to tell something (to anyone). Don't worry, I'll keep your secret. I won't even open my mouth. Have no fear. I won't utter a word.
See also: mouth, not, open

not open one's mouth

Also, shut one's mouth; not say or utter a word . Be silent, repress one's feelings or opinions, keep a secret. For example, Don't worry, I'm not going to open my mouth on this issue, or She promised not to say a word about it to anyone. Also see hold one's tongue; keep one's mouth shut.
See also: mouth, not, open

open your (big) ˈmouth

(informal) say something when you should not: Why do you always have to open your big mouth? Can’t you just keep quiet sometimes?
See also: mouth, open
References in periodicals archive ?
Some dogs won't open their mouths no matter how hard you pinch their car, and others will scream bloody murder.
Tamil girls usually don't talk about sexual abuse, they won't open their mouths about it, but I heard the officers were giving the women money or food in return for sex.
For some reason, and you would have ask them why, there are supporters at Parkhead who won't open their mouths unless they are barracking one of their own.
But the Germans sitting in the same meeting won't open their mouths.