1
general::
Phrase(s): foam at the mouth
1. 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.
McGrawhill's American Idioms And Phrasal Verbs
2
general::
Be extremely angry, as in She was foaming at the mouth over the judge's ruling. This hyperbolic term uses the verb foam in the sense of "froth at the mouth," a usage generally applied to animals such as horses and dating from about A.D. 950. [1400s]
American Heritage Idioms