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 …—
Robert Houston
Robert Houston
mysteriousness
noun
Synonyms of mysterious
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
Boards of Canada have concluded their mysterious, monthlong teaser campaign by announcing Inferno, the Scottish duo’s first album since 2013.
—Alex Suskind, Pitchfork, 22 Apr. 2026
After being attacked by a knife-wielding assailant, he’s injected with mysterious chemicals, which grant him his shapeshifting powers.
—Giana Levy, Variety, 22 Apr. 2026
At least 12 other people, the vast majority involved in nuclear science and space research, have died or gone missing since 2022, some under mysterious circumstances.
—Peter D'abrosca, FOXNews.com, 22 Apr. 2026
These observations suggest that small, mysterious moons with surprisingly different natures are the source of the particles that make up the two outermost rings, and that there are probably even more undiscovered moons to add to the 29 already known around Uranus.
—Keith Cooper, Space.com, 22 Apr. 2026
See All Example Sentences for mysterious
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Alex Suskind, Pitchfork, 22 Apr. 2026
After being attacked by a knife-wielding assailant, he’s injected with mysterious chemicals, which grant him his shapeshifting powers.
—Giana Levy, Variety, 22 Apr. 2026
At least 12 other people, the vast majority involved in nuclear science and space research, have died or gone missing since 2022, some under mysterious circumstances.
—Peter D'abrosca, FOXNews.com, 22 Apr. 2026
These observations suggest that small, mysterious moons with surprisingly different natures are the source of the particles that make up the two outermost rings, and that there are probably even more undiscovered moons to add to the 29 already known around Uranus.
—Keith Cooper, Space.com, 22 Apr. 2026
See All Example Sentences for mysterious
Cite this Entry
“Mysterious.” Merriam-Webster.com Dictionary, Merriam-Webster, https://www.merriam-webster.com/dictionary/mysterious. Accessed 25 Apr. 2026.
Copy CitationKids 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
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