keep one's mouth shut

VERB
21 LETTERS · STARTS WITH K

keep one's mouth shut is a valid 21-letter word worth 31 points in Scrabble and 34 points in Words with Friends.

SCRABBLE WORDS WITH FRIENDS
K5E1E1P3O1N1E1'0S1M3O1U1T1H4S1H4U1T1
5 + 1 + 1 + 3 + 0 + 1 + 1 + 1 + 0 + 1 + 0 + 3 + 1 + 1 + 1 + 4 + 0 + 1 + 4 + 1 + 1 =31 PTS
DOUBLE WORD → 62TRIPLE WORD → 93
MEANING

What does keep one's mouth shut mean?

VERB · 1 SENSE
1

Refrain from divulging sensitive information; keep quiet about confidential information.