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Synonyms

mysterious

American  
[mi-steer-ee-uhs] / mɪˈstɪər i əs /

adjective

  1. full of, characterized by, or involving mystery.

    a mysterious occurrence.

    Synonyms:
    cryptic, occult, esoteric, secret
  2. implying or suggesting a mystery.

    a mysterious smile.

  3. of obscure nature, meaning, origin, etc.; puzzling; inexplicable.

    a mysterious inscription on the ancient tomb.

    Synonyms:
    impenetrable, enigmatic, incomprehensible, unintelligible, unfathomable

mysterious British  
/ mɪˈstɪərɪəs /

adjective

  1. characterized by or indicative of mystery

  2. puzzling, curious, or enigmatic

"Collins English Dictionary — Complete & Unabridged" 2012 Digital Edition © William Collins Sons & Co. Ltd. 1979, 1986 © HarperCollins Publishers 1998, 2000, 2003, 2005, 2006, 2007, 2009, 2012

Synonym Usage

Mysterious, inscrutable, mystical, obscure refer to that which is not easily comprehended or explained. That which is mysterious, by being unknown or puzzling, excites curiosity, amazement, or awe: a mysterious disease. Inscrutable applies to that which is impenetrable, so enigmatic that one cannot interpret its significance: an inscrutable smile. That which is mystical has a secret significance, such as that attaching to certain rites or signs: mystical symbols. That which is obscure is discovered or comprehended dimly or with difficulty: obscure motives.

Other Word Forms

Etymology

Origin of mysterious

First recorded in 1610–20; mystery 1 + -ous

Explanation

Something that is mysterious has a secret-like quality that makes it hard to understand or define, like your mysterious answers that made your friends curious about what you were really up to. A dark shadow skims across the surface of lake...a strange disease makes a city's inhabitants violently ill...a large, hairy creature is spotted wandering in the woods. These situations are all mysterious because we don't know their causes. You can see the word mystery in mysterious. A mystery is a hidden or secret thing, so something that is mysterious takes effort to understand, unless it is beyond our comprehension.

Keep Reading on Vocabulary.com

Vocabulary lists containing mysterious

Example Sentences

Examples are provided to illustrate real-world usage of words in context. Any opinions expressed do not reflect the views of Dictionary.com.

See Examples For:

The host of “Otherworld” podcast had spoken to someone who experienced something unexplained at the mysterious dome in the Mojave Desert.

From Los Angeles Times Sep. 1, 2026

Alan Ritchson will pop in as a guest star, as Neagley investigates the mysterious death of an old friend.

From MarketWatch Aug. 31, 2026

They also reexamined mysterious stem insect fossils from the Early Devonian chert deposits of Britain and the Late Carboniferous Mazon Creek biota in the United States.

From Science Daily Aug. 27, 2026

I wrote in this space in October 2018 about a mysterious Iraqi blogger writing under the name “Mosul Eye.”

From The Wall Street Journal Aug. 27, 2026

Ordinary kids who had nothing to do with a strange plane or ghost stories or mysterious letters.

From "Found" by Margaret Peterson Haddix

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