keep a civil tongue in (one's) head

keep a civil tongue in (one's) head

To speak kindly and politely. Please try to keep a civil tongue in your head the next time you talk to Mary, instead of arguing with her, OK?
See also: civil, head, keep, tongue
Farlex Dictionary of Idioms.

keep a civil tongue in one's head

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).
See also: civil, head, keep, tongue
The American Heritage® Dictionary of Idioms by Christine Ammer.

keep a civil tongue in your head

speak politely and calmly, without rudeness.
See also: civil, head, keep, tongue
Farlex Partner Idioms Dictionary
See also:
  • keep a civil tongue in one's head
  • keep a civil tongue in your head
  • keep a civil tongue
  • Would you please?
  • if you don't mind
  • If you don't mind!
  • on the tip of (one's) tongue
  • on the tip of one's tongue
  • give tongue
  • hold one's tongue, to