put (one's) foot in (one's) mouth

put (one's) foot in (one's) mouth

To unintentionally say something foolish, tactless, or offensive. He just tends to put his foot in his mouth when he's forced to speak for too long, so try to get him off stage as soon as possible. Oh man, did I ever put my foot in my mouth—I just congratulated Sarah's sister on being pregnant. She isn't.
See also: foot, mouth, put
Farlex Dictionary of Idioms.

put one's foot in one's mouth

 and put one's foot in it; stick one's foot in one's mouth
Fig. to say something that you regret; to say something stupid, insulting, or hurtful. When I told Ann that her hair was more beautiful than I had ever seen it, I really put my foot in my mouth. It was a wig. I put my foot in it by telling John's secret; he found out.
See also: foot, mouth, put
McGraw-Hill Dictionary of American Idioms and Phrasal Verbs.

foot in one's mouth, put one's

Say something foolish, embarrassing, or tactless. For example, Jane put her foot in her mouth when she called him by her first husband's name. This notion is sometimes put as having foot-in-mouth disease, as in He has a bad case of foot-in-mouth disease, always making some tactless remark. The first expression dates from about 1900. The variant, dating from the mid-1900s, is a play on the foot-and-mouth (sometimes called hoof-and-mouth) disease that afflicts cattle, causing eruptions to break out around the mouth and hoofs.
See also: foot, put
The American Heritage® Dictionary of Idioms by Christine Ammer.

put (one's) foot in (one's) mouth

To make a tactless remark.
See also: foot, mouth, put
American Heritage® Dictionary of the English Language, Fifth Edition.
See also:
  • foot in one's mouth, put one's
  • put foot in mouth
  • stick (one's) foot in (one's) mouth
  • foot-in-mouth disease
  • put (one's) foot in it
  • put one's foot in it
  • put your foot in it
  • if you keep your mouth shut, you won't put your foot in it
  • clanger
  • drop a brick/clanger