monster

American  

[mon-ster] / ˈmɒn stər /

noun

monsters plural

1. a nonhuman creature so ugly or monstrous as to frighten people.

2. any creature grotesquely deviating from the normal shape, behavior, or character.

3. a person who provokes or elicits horror by wickedness, cruelty, etc.

   Synonyms:

   miscreant, devil, demon, brute, fiend

4. any animal or thing huge in size.

5. a legendary animal combining features of animal and human form or having the forms of various animals in combination, as a centaur, griffin, or sphinx.

6. Biology.

   1. an animal or plant of abnormal form or structure, as from marked malformation or the absence of certain parts or organs.

   2. a grossly anomalous fetus or infant, especially one that is not viable.

7. anything unnatural or monstrous.

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adjective

1. huge; enormous; monstrous.

   a monster tree.

monster British  

/ ˈmɒnstə /

noun

1. an imaginary beast, such as a centaur, usually made up of various animal or human parts

2. a person, animal, or plant with a marked structural deformity

3. a cruel, wicked, or inhuman person

4. 1. a very large person, animal, or thing

   2. ( as modifier )

      a monster cake

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verb

1. informal to criticize (a person or group) severely

2. sport to use intimidating tactics against (an opponent)

monster Idioms  

1. see green-eyed monster.

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Other Word Forms

Derived Forms

• monsterlike
  adjective

Inflected Forms

Nouns

• monsters
  plural

Etymology

Origin of monster

First recorded in 1250–1300; Middle English monstre, from Latin mōnstrum “portent, unnatural event, monster,” from mon(ēre) “to warn” + -strum, noun suffix

Explanation

Monsters are imaginary scary creatures that lurk in dark places and horror movies. If it's got 3 heads, shark teeth and lives under your bed, then it's probably a monster. Monsters are big. Monsters are hairy. And monsters are certainly scary. Think of the Abominable Snow Man, that Loch Ness creature, or even Shrek — even though he's technically an ogre. This word isn't only for the imaginary, though: you could call anything freakish, frightening, or particularly evil a monster, like a cruel murderer or even a really big, violent storm.

Example Sentences

Gray Monster, a newsletter aimed at caregivers, plays off this dynamic with its slogan: “Gray Monster helps because we know your brother won’t.”

From MarketWatch • Jun. 30, 2026

Audiences have clearly latched onto the stories, said Jason Blum of Blumhouse–Atomic Monster, who worked on both films.

From Los Angeles Times • Jun. 20, 2026

Looking at the daily chart, Vita Coco has demonstrated impressive relative strength against beverage peer Monster Beverage Corporation over the past year as seen on the ratio chart.

From Barron's • Jun. 17, 2026

The Official Monster Raving Loony Party has named its leader and co-founder - Alan Hope - otherwise known as Alan "Howlin" Laud Hope.

From BBC • May 19, 2026

“Aw, c’mon, Annabeth. Monster Donut doesn’t mean monsters! It’s a chain. We’ve got them in New York.”

From "The Sea of Monsters" by Rick Riordan

Related Words

• behemoth
• freak
• giant
• whale