1. full of, characterized by, or involving mystery: a mysterious occurrence.
  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.

Origin of mysterious

First recorded in 1610–20; mystery1 + -ous
Related formsmys·te·ri·ous·ly, adverbmys·te·ri·ous·ness, nounqua·si-mys·te·ri·ous, adjectivequa·si-mys·te·ri·ous·ly, adverbun·mys·te·ri·ous, adjectiveun·mys·te·ri·ous·ly, adverbun·mys·te·ri·ous·ness, noun

Synonyms for mysterious

Synonym study

1. 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. Unabridged Based on the Random House Unabridged Dictionary, © Random House, Inc. 2018

Examples from the Web for mysteriousness

Historical Examples of mysteriousness

  • She was mysterious, with the mysteriousness of living beings.

    The Secret Agent

    Joseph Conrad

  • Janzen was at last emerging from his wonted frigidity and mysteriousness.

  • I may be able to very soon, and clear up all this mysteriousness, that is worrying me so.

  • He was impressed and interested by the mysteriousness of the effect.


    Joseph Conrad

  • The mysteriousness of his quickened heart-beats startled him.

    Under Western Eyes

    Joseph Conrad

British Dictionary definitions for mysteriousness


  1. characterized by or indicative of mystery
  2. puzzling, curious, or enigmatic
Derived Formsmysteriously, adverbmysteriousness, noun
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

Word Origin and History for mysteriousness



1610s, "full of mystery," from Latin mysterium (see mystery (n.1)) + -ous. Related: Mysteriously; mysteriousness. Earlier in same sense was mysterial (early 15c.), from Late Latin mysterialis.

Online Etymology Dictionary, © 2010 Douglas Harper