Foot in mouth is the habit of saying exactly the wrong thing. A bad case of foot in mouth.
It names a tendency rather than a single blunder, which is what separates it from the phrase about a single occasion. The joke plays on foot-and-mouth, the cattle disease.
1phrasefoot in mouthThe habit of saying exactly the wrong thing.
“He has a talent for foot in mouth at weddings.”
foot in mouth is a phrase.
Practised in Idioms