monster

American  

[mon-ster] / ˈmɒn stər /

noun

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

• monsterlike adjective

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

Theatrical business did pick up shortly after last year’s CinemaCon with a monster showing for Warner Bros.’

From Los Angeles Times • Apr. 13, 2026

Together, we filled in the backstory for a monster movie that would begin in media res, offering no answers of its own.

From Salon • Apr. 12, 2026

Jacob Elordi, who plays Cassie's husband Nate, was nominated for an Oscar this year for playing the monster in Guillermo del Toro's Frankenstein.

From BBC • Apr. 8, 2026

Recognize that we’ve created a healthcare system monster that needs reform by removing layers of expensive administrative costs.

From The Wall Street Journal • Apr. 6, 2026

And if it was a monster they wanted, a monster they would get.

From "The Undead Fox of Deadwood Forest" by Aubrey Hartman

Related Words

• behemoth
• freak
• giant
• whale