mysterious

adjective

mys·​te·​ri·​ous mi-ˈstir-ē-əs 

1

a

: of, relating to, or constituting mystery

the mysterious ways of God

b

: exciting wonder, curiosity, or surprise while baffling efforts to comprehend or identify : mystifying

heard a mysterious noise

a mysterious stranger

a mysterious plane crash

a mysterious illness

2

: stirred by or attracted to the inexplicable

… to help a mysterious wizard … ward off the end of the world with blood sacrifices.

—Robert Houston

mysteriousness noun

Synonyms

• arcane
• cryptic
• deep
• enigmatic
• enigmatical
• impenetrable
• inscrutable
• mystic
• occult
• uncanny

Examples of mysterious in a Sentence

the mysterious ways of nature

We heard a mysterious noise outside our tent.

He died under mysterious circumstances.

A mysterious illness has been spreading through the city.

There's something mysterious about that old woman.

Her behavior was very mysterious.

Recent Examples on the Web

In the game, Abby is introduced as a woman on a mysterious mission alongside her friends Mel (Ariela Barer), Nora (Tati Gabrielle), Owen (Spencer Lord) and Manny (Danny Ramirez). —Taijuan Moorman, USA TODAY, 20 Feb. 2025

There have been numerous mysterious fires and explosions in Russia since Putin ordered a full-scale invasion of Ukraine on February 24, 2022. —Dan Perry, Newsweek, 20 Feb. 2025

The world’s waters are deep and mysterious places, and the best fishermen are good at keeping secrets. —Dac Collins, Outdoor Life, 20 Feb. 2025

The investigation finds Reacher smack dab in the center of a mysterious rug import business called Bizarre Bazaar. —Chris Gardner, The Hollywood Reporter, 20 Feb. 2025

Word History

Etymology

mystery entry 1 + -ous, probably after Middle French mysterieux

First Known Use

1578, in the meaning defined at sense 1a

Phrases Containing mysterious

• be mysterious

Rhymes for mysterious

• delirious
• imperious
• cereus
• nereus
• serious
• sirius
• deleterious

Kids Definition

mysterious

adjective

mys·​te·​ri·​ous mis-ˈtir-ē-əs 

: containing, suggesting, or presenting a mystery

mysterious noises

also : difficult or impossible to understand

the mysterious ways of nature

mysteriously adverb