Foaming at the Mouth – Idiom, Meaning & Origin

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Candace Osmond

Candace Osmond studied Advanced Writing & Editing Essentials at MHC. She’s been an International and USA TODAY Bestselling Author for over a decade. And she’s worked as an Editor for several mid-sized publications. Candace has a keen eye for content editing and a high degree of expertise in Fiction.

At least once, you’ve probably come across someone so angry they were foaming at the mouth. But does this mean they had literal foam coming out of their mouth? Or is there more to this phrase than meets the eye? Well, get ready for some frothy insights! Plus, I’ll look at the difference between frothing and foaming at the mouth.

Foaming at the Mouth Meaning Defined

Foaming at the Mouth – Idiom Meaning Origin

We use foaming at the mouth as an idiom to signify extreme anger, excitement or eagerness, to the point where someone might seem out of control. No, there’s no actual foam involved — it’s just a metaphorical expression!

Origin and Etymology of Foaming at the Mouth

Foaming at the Mouth Ngram
Foaming at the mouth usage trend.

This phrase originates from the animal kingdom and observing animals, particularly rabid dogs, which produce foamy saliva around their mouths when affected by rabies. So, they’re literally foaming at the mouth. It began to be used metaphorically in English during the 16th century to describe intense anger or excitement in humans.

Frothing at the Mouth vs. Foaming at the Mouth

Frothing at the mouth and foaming at the mouth are often used in place of one another because both conjure the image of someone so impassioned that they seem to have lost control. But frothing can also relate to being extremely enthusiastic or eager about something, especially food!

Foaming at the Mouth Synonyms

There are endless ways to describe someone being beyond angry, but here are a few common alternatives to saying foaming at the mouth.

  • Seething with rage
  • Steaming mad
  • Fuming
  • Raging
  • Mad as a hen
  • Boiling over
  • Enraged
  • Livid
  • Furious
  • Irate
  • Spitting feathers

Foaming at the Mouth Examples in a Sentence

Foaming at the Mouth – Idiom Meaning Origin 1 1

Seeing a phrase used in a full sentence is one of the easiest ways to understand what it means.

  • When he found out his team had lost, Brad practically foamed at the mouth with rage.
  • She was foaming at the mouth at the thought of the upcoming sale at her favorite store.
  • When the politician was asked about the scandal, he began to foam at the mouth, vehemently denying all accusations.
  • He was foaming at the mouth, eager to get his hands on the new video game release.
  • When she found out her daughter had been bullied, she was foaming at the mouth and ready to confront the school.
  • The fans were foaming at the mouth in anticipation of the band’s performance.
  • The opportunity to finally prove his worth had him foaming at the mouth with excitement.
  • He was foaming at the mouth when he discovered his car had been towed.
  • She was practically foaming at the mouth with the excitement of the upcoming trip.
  • He was foaming at the mouth with fury when he found out his project had been sabotaged.

Frothing or Foaming?

So there you have it! Whether you’re foaming or frothing at the mouth, it’s all about high levels of excitement or anger. Although, I tend to froth at the mouth at the sight of a delicious meal like homemade spaghetti and garlic bread! Be sure to have a look at my other quick idiom guides to level up your vocabulary!

Want to know more idioms? Check out some of the phrases we have below: