Loose lips sink ships

Also found in: Acronyms.

Loose lips sink ships.

Don't talk carelessly because you don't know who is listening. (From wartime. Literally, "Don't reveal even the location of a loved one on a ship, because the location could be communicated to the enemy by a spy.") You never know who is going to hear what you say and how they will use what they hear. Remember, loose lips sink ships.
See also: lip, loose, ship, sink
References in periodicals archive ?
Working for the government, we know that loose lips sink ships.