foam

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.

See also: mouth

foam up

[for something, such as soap or milk] to make foam or lather. Milk will foam up when it is boiled. The boiling soup foamed up and slopped over the pot.

See also: up

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foaming at the mouth

very angry The court's decision has left bloodsport enthusiasts foaming at the mouth.

See also: mouth

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foam at the mouth

1. to be uncontrollably excited The band's high-energy music left the crowd foaming at the mouth for more.

2. to be uncontrollably angry And there was my mom, still foaming at the mouth, still shouting at my brother.

Etymology: based on the literal meaning of foam at the mouth (to have an illness that causes liquid and bubbles to collect around the mouth)

See also: mouth