monster

1 of 2

noun

mon·​ster ˈmän(t)-stər 

plural monsters

1

a

: an animal of strange or terrifying shape

a mythical monster

a sea monster

… visualize this scaleless monster, eight or nine feet long, sprawling in the shade by the side of the mud pools …

—W. E. Swinton

b

informal : one unusually large for its kind

That truck is a monster.

That's why I was born in my grandmother's house—a grand, brick Federal monster of a house.

—John Irving

2

a

: an animal or plant of abnormal form or structure

b

: one who deviates from normal or acceptable behavior or character

an immoral monster

3

: a threatening force

… the same monster—Destiny … that rolls every civilization to doom …

—W. L. Sullivan

4

: something monstrous

especially : a person of unnatural or extreme ugliness, deformity, wickedness, or cruelty

a cruel monster of a boss

5

: one that is highly successful

That movie was a monster at the box office.

monster

2 of 2

adjective

: enormous or impressive especially in size, extent, or numbers

Synonyms of monster

Noun

• demon
• grotesque
• ogre

Adjective

• giant
• gigantic
• huge
• enormous
• vast
• massive
• colossal
• tremendous
• mammoth
• monstrous
• bumper
• monumental
• titanic
• astronomical
• immense

Examples of monster in a Sentence

Noun

That car is a monster.

Inflation has become an economic monster.

Adjective

The movie turned out to be a monster hit.

Recent Examples on the Web

Noun

In Percy Jackson and the Olympians, the Disney+ series adapted from Rick Riordan's bestselling book series, Walker Scobell plays the titular character, a demigod navigating the dangerous world of gods and monsters. —Julia Moore, PEOPLE, 9 Jan. 2026

This bakery, which has been serving Louisville since 1924, offers a wide variety of Mardi Gras items, from King Cakes to cookies, thumbprints, cupcakes and the popular cookie monsters. —Gege Reed, Louisville Courier Journal, 8 Jan. 2026

Adjective

The Athletic's Jim Bowden recently predicted the Blue Jays would re-sign Bichette on a monster seven-year, $189 million deal this winter. —Zach Pressnell, MSNBC Newsweek, 6 Dec. 2025

Bryce Young's monster fourth-and-2 touchdown to Tetairoa McMillan to take a fourth-quarter lead against the Rams requires some different care. —Derrik Klassen, New York Times, 3 Dec. 2025

Word History

Etymology

Noun

Middle English monstre, from Anglo-French, from Latin monstrum omen, monster, from monēre to warn — more at mind

Adjective

from attributive use of monster entry 1

First Known Use

Noun

14th century, in the meaning defined at sense 1a

Adjective

1837, in the meaning defined above

Phrases Containing monster

• Gila monster
• green-eyed monster
• Loch Ness monster
• party monster
• sea monster

Kids Definition

monster

1 of 2 noun

mon·​ster ˈmän(t)-stər 

1

: an animal or plant of abnormal form or structure

2

: a strange or horrible creature

3

: something unusually large

4

: an extremely wicked or cruel person

monster

2 of 2 adjective

: very large : enormous