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Synonyms

mysterious

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

adjective

  1. An image of the word mysterious as defined by full of, characterized by, or involving mystery.

    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 findings raise the possibility that some mysterious cosmic flashes, whose sources have been difficult to explain, may actually come from merging neutron stars.

From Science Daily ● Sep. 30, 2026

On that critical investigation rests the decision over whether to arrest anyone else, whether to charge the five men, and whether we ever find out the true story of the mysterious RAF Fairford plot.

From BBC ● Sep. 29, 2026

He wanted to see who could keep them steady, they recalled, to help him with a mysterious task.

From The Wall Street Journal ● Sep. 28, 2026

As does “Hoffa,” the 1992 drama, both gritty and glamorous, about the life of labor organizer Jimmy Hoffa, who is now largely known for the mysterious and still unexplained circumstances of his disappearance in 1975.

From Los Angeles Times ● Sep. 25, 2026

She turned to the mysterious professor on her left and motioned him forward.

From "Glitch" by Laura Martin

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