Dictionary Home » The American Heritage Dictionary of Idioms » keep a civil tongue in one's head

keep a civil tongue in one's head

keep a civil tongue in one's head idiom

Speak politely, as in The teacher won't allow swearing; she says we must keep a civil tongue in our heads. This expression uses tongue in the sense of “a manner of speaking,” a usage dating from the 1400s. An early cautionary version was “Keep a good tongue in your head, lest it hurt your teeth” (1595).

The American Heritage® Dictionary of Idioms by Christine Ammer. Copyright © 2003, 1997 by The Christine Ammer 1992 Trust. Published by Houghton Mifflin Harcourt Publishing Company. All rights reserved.