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Synonyms

dubious

American  
[doo-bee-uhs, dyoo-] / ˈdu bi əs, ˈdju- /

adjective

  1. doubtful; marked by or occasioning doubt.

    a dubious reply.

    Synonyms:
    unclear, obscure, ambiguous, equivocal
  2. of doubtful quality or propriety; questionable.

    a dubious compliment; a dubious transaction.

  3. of uncertain outcome.

    in dubious battle.

  4. wavering or hesitating in opinion; inclined to doubt.

    Synonyms:
    hesitant, uncertain, undecided

dubious British  
/ ˈdjuːbɪəs /

adjective

  1. marked by or causing doubt

    a dubious reply

  2. unsettled in mind; uncertain; doubtful

  3. of doubtful quality; untrustworthy

    a dubious reputation

  4. not certain in outcome

"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

See doubtful.

Other Word Forms

Etymology

Origin of dubious

First recorded in 1540–50; from Latin dubius; cf. doubt ( def. )

Explanation

Choose the adjective dubious for something you have doubts about or you suspect is not true. That bridge you just "bought" might be of dubious value. Dubious stems from Latin dubiosus, "doubtful" or "uncertain," and contains the Latin root duo in this case meaning "of two minds." This is apparent in that dubious generally describes something that appears one way but is truly another. A dubious claim is probably not true, whereas a dubious website or character is of questionable quality. Dubious can also be synonymous with doubtful, as in "she was dubious about the idea."

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Vocabulary lists containing dubious

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:

Despite the dangers, influencers with hundreds of thousands of followers on Instagram or TikTok promote private clinics or beauty salons that experts say are dubious.

From Barron's Jul. 17, 2026

After doubling down on this case, Blanche oversaw a highly dubious indictment that accused Abrego Garcia of human smuggling.

From Slate Jul. 9, 2026

At best, he is a trillionaire on paper, but even that description is dubious.

From Los Angeles Times Jul. 1, 2026

The aircraft carrier USS Gerald R. Ford was deployed for nearly a year, a dubious post-Vietnam record.

From The Wall Street Journal Jun. 25, 2026

Indeed, this used to be the main argument of opponents of black holes: how could one believe in objects for which the only evidence was calculations based on the dubious theory of general relativity?

From "A Brief History of Time: And Other Essays" by Stephen Hawking

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