mys·​te·​ri·​ous mi-ˈstir-ē-əs How to pronounce mysterious (audio)
: of, relating to, or constituting mystery
the mysterious ways of God
: 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
: 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

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 Edgardo’s initiation into an uncharted domain feels both mysterious and mythical. Armond White, National Review, 31 May 2024 Physicists consider black holes one of the most mysterious objects that exist. Gaurav Khanna, Discover Magazine, 27 May 2024 Jones plays Suzie, a woman living in Kyoto whose life is upended by the disappearance of her son and husband in a mysterious plane crash. Lucy Ford, TIME, 23 May 2024 Despite the fact that they’re created by humans, large language models are still quite mysterious. Lucas Ropek / Gizmodo, Quartz, 23 May 2024 See all Example Sentences for mysterious 

These examples are programmatically compiled from various online sources to illustrate current usage of the word 'mysterious.' Any opinions expressed in the examples do not represent those of Merriam-Webster or its editors. Send us feedback about these examples.

Word History


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

First Known Use

1578, in the meaning defined at sense 1a

Time Traveler
The first known use of mysterious was in 1578

Dictionary Entries Near mysterious

Cite this Entry

“Mysterious.” Dictionary, Merriam-Webster, Accessed 16 Jun. 2024.

Kids Definition


mys·​te·​ri·​ous mis-ˈtir-ē-əs How to pronounce mysterious (audio)
: containing, suggesting, or presenting a mystery
mysterious noises
also : difficult or impossible to understand
the mysterious ways of nature
mysteriously adverb

More from Merriam-Webster on mysterious

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