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

Example Sentences

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. See More
Recent Examples on the Web In other words, letting the public think an object is mysterious or unexplained is a good way of disguising something that’s explainable but should be secret. Kelsey D. Atherton, Popular Science, 23 Jan. 2023 The line between avoidance and evasion is not mysterious. Evan Osnos, The New Yorker, 16 Jan. 2023 Outside its grand gates, the Agojie are mysterious, revered and feared. Karen M. Peterson, Variety, 12 Jan. 2023 The massive object at the heart of Mexico’s largest and most popular museum is so mysterious that nobody knows quite what to call it. John J. Miller, WSJ, 6 Jan. 2023 The entrance to The Madrona is a little mysterious. Laurie Werner, Forbes, 27 Dec. 2022 This world is so mysterious, and new Pokemon are discovered all the time. Vulture, 11 Nov. 2022 Much more mysterious are the mechanisms that cause these rebounds. Sam Walters, Discover Magazine, 8 Nov. 2022 That level of prolific is too mysterious and mystical to me. Jonathan Cohen, SPIN, 14 Dec. 2022 See More

These example sentences are selected automatically from various online news sources to reflect current usage of the word 'mysterious.' Views expressed in the examples do not represent the opinion of Merriam-Webster or its editors. Send us feedback.

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 2 Feb. 2023.

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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