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.

---

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

---

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.

---

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

Example Sentences

"You get the finished result of a clean monster truck, rather than a scarf."

From BBC • Apr. 3, 2026

Investors have good reason to remain cautious despite Tuesday’s monster quarter-end rally.

From MarketWatch • Mar. 31, 2026

County was and remains a Frankenstein’s monster, dozens of cities stitched awkwardly together.

From Los Angeles Times • Mar. 26, 2026

“Industrials are off to a monster start in 2026,” wrote Trivariate Research founder Adam Parker External link in a recent report.

From Barron's • Mar. 25, 2026

Clara stayed in the doorway, unsure of just how much of the monster her sister had unleashed.

From "Night Owls" by A.R. Vishny

Related Words

• behemoth
• freak
• giant
• whale