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

While the roots of the plot remain uncertain, some particulars are clear: Belgian authorities arrested a young couple Saturday in a Brussels suburb. NBC News, "Was it an Iranian terror plot or a false flag operation?," 6 July 2018 Even for farmers signing on with Scioto, the future remains uncertain. Kate Talerico, The Courier-Journal, "As Dean Milk contract ends, some farmers pick up a last-minute hope," 29 June 2018 Whether all the Democrats would stick together, however, remains uncertain. Jackie Calmes, latimes.com, "Both sides mobilize for a Senate 'battle of the ages' focused on one issue — abortion," 27 June 2018 Whether the Angara booster can capture anything close to the Proton's once highly profitable share of the global launch market remains highly uncertain. Eric Berger, Ars Technica, "Russia’s Proton rocket, which predates Apollo, will finally stop flying," 25 June 2018 But the outlook for help from Washington remains uncertain. Bill Turque, kansascity, "Taxes for KC Streetcar extension to UMKC approved by wide margin in mail-in ballots," 20 June 2018 But polls show even stronger opposition to ending the DACA program, yet the future of immigrants who benefit from it remains uncertain. Michael Smolens, sandiegouniontribune.com, "Trump creates kids crisis to leverage border wall, immigration limits," 18 June 2018 With America’s lust for energy (the U.S. accounts for 18 percent of the world's energy consumption), the impacts on frontline families remains uncertain. Megan Ditrolio, Marie Claire, "Fracking: The Environmental Crisis in Our Backyard," 13 June 2018 Dickens confirmed the looming return of the legendary HBO series during her final appearance on Talking Dead; while the totality of Dickens' next moves remains uncertain, at least one of her future projects will have roots in her past. Josh Wigler, The Hollywood Reporter, "'Fear the Walking Dead' Star "Disappointed" to Be Leaving AMC Spinoff," 11 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

10 Nov 2018

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Time Traveler for uncertain

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

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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).


by force of circumstances

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