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
The crew might also spy distinct flashes of light as space rocks strike the moon — or dust floating above the edge of the moon, a mysterious phenomenon scientists have yet to understand fully.
—Ashley Strickland, CNN Money, 21 Feb. 2026
Ramos plays a mysterious assassin named Antonio, who has been hired by Kutcher's billionaire character, Byron Forst, to be his personal hitman.
—Lauren Huff, Entertainment Weekly, 20 Feb. 2026
His calm authority, wit, and quiet moral certainty is challenged by escalating reports of a mysterious affliction hitting the inhabitants of New York and beyond.
—Melanie Goodfellow, Deadline, 19 Feb. 2026
Brandi Glanville finally has some answers about what caused her mysterious facial issues — her breast implants.
—Tracy Brown, Los Angeles Times, 19 Feb. 2026
See All Example Sentences for mysterious
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Ashley Strickland, CNN Money, 21 Feb. 2026
Ramos plays a mysterious assassin named Antonio, who has been hired by Kutcher's billionaire character, Byron Forst, to be his personal hitman.
—Lauren Huff, Entertainment Weekly, 20 Feb. 2026
His calm authority, wit, and quiet moral certainty is challenged by escalating reports of a mysterious affliction hitting the inhabitants of New York and beyond.
—Melanie Goodfellow, Deadline, 19 Feb. 2026
Brandi Glanville finally has some answers about what caused her mysterious facial issues — her breast implants.
—Tracy Brown, Los Angeles Times, 19 Feb. 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 23 Feb. 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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