- foam at the mouth
- foam at the mouth1. Lit. to create froth or foam around the mouth, as with some diseases. •
The poor dog was foaming at the mouth and looked quite dangerous.
•What does it mean when a cow foams at the mouth?
2. Fig. to be extraordinarily angry. •She was almost foaming at the mouth when she heard about the cost of the car repairs.
•Walter was foaming at the mouth with rage.
* * *{v. phr.}, {slang} To be very angry, like a mad dog. * /By the time Uncle Henry had the third flat tire he was really foaming at the mouth./
Dictionary of American idioms. 2013.