un·​cer·​tain | \ ˌən-ˈsər-tᵊn \

Definition of uncertain

1a : not known beyond doubt : dubious an uncertain claim
b : not having certain knowledge : doubtful remains uncertain about her plans
c : not clearly identified or defined a fire of uncertain origin
2 : not constant : variable, fitful an uncertain breeze
3 : indefinite, indeterminate the time of departure is uncertain
4 : not certain to occur : problematical his success was uncertain
5 : not reliable : untrustworthy an uncertain ally

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Other Words from uncertain

uncertainly adverb
uncertainness \ ˌən-​ˈsər-​tᵊn-​(n)əs \ noun

Examples of uncertain in a Sentence

The time of departure is still uncertain. We are still uncertain of the truth. She remains uncertain about her plans. I'm uncertain about how to respond. The cause of the fire is uncertain. He has an uncertain temper. They face a financially uncertain future.
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Recent Examples on the Web

For some, not knowing your history can make the future seem even more uncertain. Fiona Tapp, SELF, "What It’s Like to Fill in the Gaps in Your Health History When You’re Adopted," 18 Jan. 2019 But as the war against Islamic State winds down and the U.S. gives mixed signals about its intentions to leave Syria, the fate of the Kurds and the foreign fighters in their prisons is increasingly uncertain. Raja Abdulrahim, WSJ, "Foreign Fighters Are Held in Syria as Home Countries Refuse Their Return," 7 Jan. 2019 The cyclist was reported to be conscious and breathing; police are uncertain whether anyone was transported to the hospital. Alyson Ward, Houston Chronicle, "Train strikes bicyclist in southeast Houston," 10 June 2018 Even more uncertain is whether — and when — a bike lane might be added to the west span of the Bay Bridge, allowing cyclists to pedal between San Francisco and the East Bay. Michael Cabanatuan, San Francisco Chronicle, "Bay Bridge to test 24-hour bike and pedestrian path," 3 May 2018 The fate of the planet and existence itself has never been more uncertain as everything the Avengers have fought for has led up to this moment. Joey Morona, cleveland.com, "Movie Minute: 'Avengers: Infinity War' eyes record opening weekend," 26 Apr. 2018 The plot began when Warren Harding was nominated to head the Republican ticket in 1920, but even today, the conspiracy’s precise scope remains uncertain. Andrew Coan, WSJ, "Why Robert Mueller’s Predecessors Usually Didn’t Prevail," 25 Jan. 2019 However, AlSayyad’s active employment status has remained uncertain as the internal investigation conducted through the Committee on Privilege and Tenure chugged along. Kelsey Keith, Curbed, "UC Berkeley suspends professor for sexual harassment, citing ‘voluminous evidence’," 21 Aug. 2018 The fate of Proposition C, a ballot measure that would raise taxes on commercial landlords in San Francisco to fund a variety of child care services, remained uncertain on Thursday, two days after voters went to the polls. Dominic Fracassa, SFChronicle.com, "SF’s Prop. C child-care measure still undecided, but lead has shrunk," 7 June 2018

These example sentences are selected automatically from various online news sources to reflect current usage of the word 'uncertain.' Views expressed in the examples do not represent the opinion of Merriam-Webster or its editors. Send us feedback.

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First Known Use of uncertain

14th century, in the meaning defined at sense 3

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Statistics for uncertain

Last Updated

17 Feb 2019

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Time Traveler for uncertain

The first known use of uncertain was in the 14th century

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More Definitions for uncertain



English Language Learners Definition of uncertain

: not exactly known or decided : not definite or fixed
: not sure : having some doubt about something
: not definitely known


un·​cer·​tain | \ ˌən-ˈsər-tᵊn \

Kids Definition of uncertain

1 : not exactly known or decided on an uncertain amount
2 : not sure They were uncertain of the rules.
3 : not known for sure an uncertain claim
4 : likely to change : not dependable uncertain weather

Other Words from uncertain

uncertainly adverb

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Comments on uncertain

What made you want to look up uncertain? Please tell us where you read or heard it (including the quote, if possible).


to express emotion in a dramatic way

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