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Showing results for uncertain. Search instead for incertain.
Synonyms

uncertain

American  
[uhn-sur-tn] / ʌnˈsɜr tn /

adjective

  1. not definitely ascertainable or fixed, as in time of occurrence, number, dimensions, or quality.

    Synonyms:
    unpredictable, unsure
  2. not confident, assured, or free from hesitancy.

    an uncertain smile.

  3. not clearly or precisely determined; indefinite; unknown.

    a manuscript of uncertain origin.

    Synonyms:
    undetermined, unsettled
  4. vague; indistinct; not perfectly apprehended.

    an abstruse novel with uncertain themes.

  5. subject to change; variable; capricious; unstable.

    a person of uncertain opinions.

  6. ambiguous; unreliable; undependable.

    Her loyalties are uncertain.

  7. dependent on chance or unpredictable factors; doubtful; of unforeseeable outcome or effect.

  8. unsteady or flickering, as light; of changing intensity or quality.

    Synonyms:
    irregular

uncertain British  
/ ʌnˈsɜːtən /

adjective

  1. not able to be accurately known or predicted

    the issue is uncertain

  2. not sure or confident (about)

    a man of uncertain opinion

  3. not precisely determined, established, or decided

    uncertain plans

  4. not to be depended upon; unreliable

    an uncertain vote

  5. liable to variation; changeable

    the weather is uncertain

    1. unambiguously

    2. forcefully

"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

uncertain Idioms  

Synonym Usage

Uncertain, insecure, precarious imply a lack of predictability. That which is uncertain is doubtful or problematical; it often involves danger through an inability to predict or to place confidence in the unknown: The time of his arrival is uncertain. That which is insecure is not firm, stable, reliable, or safe, and hence is likely to give way, fail, or be overcome: an insecure foundation, footing, protection. Precarious suggests great susceptibility to failure, or exposure to imminent danger: a precarious means of existence.

Other Word Forms


Etymology

Origin of uncertain

First recorded in 1250–1300; Middle English; un- 1 + certain


Explanation

To be uncertain is to be unsure of something. Also, uncertain things are undecided, unknown, or doubtful in some way. If you're certain of something, you're sure of it. When you're uncertain, you don't know. If you don't know the answer to a math question, you're uncertain. If you can't remember where you parked your car, you're uncertain about its location. Also, anything unknown or up in the air in uncertain. Trying to be a famous actor is an uncertain path. Gambling money on horses is very uncertain. And, it's certainly hard to plan for an uncertain future.

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Vocabulary lists containing uncertain

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:

But whoever wins will still be faced with the problem of rising unemployment, and an uncertain geopolitical world.

From The Wall Street Journal ● Nov. 6, 2026

“Queen at Sea” offers no answers, leaving the viewer as uncertain as Amanda, who wants to protect her mother but cannot deny how drawn Leslie is to her kindly husband.

From Los Angeles Times ● Nov. 6, 2026

For these individuals, evidence of calcium buildup may help doctors make more informed decisions when the need for statin therapy is uncertain.

From Science Daily ● Nov. 6, 2026

The defence secretary, though, faces a more uncertain political future.

From BBC ● Nov. 6, 2026

Neither would they limit themselves to the slow and equally uncertain process of seeking justice within the courts.

From "The Best of Enemies" by Osha Gray Davidson

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