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

Ward added that “I’d rather drink full-sugar, Mexican Coke or, shock, Pepsi Zero, than allow the soulless Frankenstein monster known as Diet Coke to pass my lips.”

From The Wall Street Journal • May 20, 2026

Indiana shot 53% and the Sparks went 47% from the floor, even with Cameron Brink’s monster block on Clark.

From Los Angeles Times • May 14, 2026

As a writer who is both gay and old enough to have watched the internet explode into the nefarious monster it’s become, the way language transforms online both irks and fascinates me.

From Salon • May 10, 2026

Mesidor had a monster run with Miami in the College Football Playoff, finishing with 5½ sacks and 17 total tackles.

From Los Angeles Times • Apr. 25, 2026

If he handed the keys over, he’d be letting a monster back into Rio Luna.

From "The Way to Rio Luna" by Zoraida Cordova

Related Words

• behemoth
• freak
• giant
• whale