watch one's mouth

• Audio (General Australian):

  (file)

watch one's mouth (third-person singular simple present watches one's mouth, present participle watching one's mouth, simple past and past participle watched one's mouth)

1. (idiomatic, US) To be careful about what one says, especially with regard to disrespectful or profane language.

   You really need to watch your mouth. You're a teacher now!

2. (idiomatic, chiefly US) In the imperative form, used as a warning to choose one's words carefully or else be silent, for fear of consequences.

   Hey. Watch your mouth. Don't you realize who's listening?

   • 2012, Terese Pampellonne, The Unwelcome Child:

     You watch your mouth, sis. I may be old, but I can still knock the stars out of the sky for you.

• watch one's language
• watch one's tongue