un·​cer·​tain | \ ˌən-ˈsər-tᵊn How to pronounce uncertain (audio) \

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 How to pronounce uncertainness (audio) \ 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 Two atoms can be entangled so that each is in an uncertain two-way state, but their spins are definitely correlated, say, in opposite directions. Adrian Cho, Science | AAAS, "Quantum internet closer as physicists stretch spooky link between atoms," 13 Feb. 2020 But from the moment Cass teams up with Harley, her once uncertain fate starts to change. Kelsea Stahler, refinery29.com, "If Only Everyone Could All See Birds Of Prey Through Breakout Star Ella Jay Basco’s Eyes," 12 Feb. 2020 Despite these efforts, there are critical information gaps that make planning for the outbreak more challenging and uncertain. Tom Inglesby, STAT, "Hospitals, governments need more data to prepare for the new coronavirus outbreak," 11 Feb. 2020 Scientists and medical officials remain uncertain how changing seasons might affect the virus. Kathryn Watson, CBS News, "Trump touts economic success, criticizes sanctuary cities in meeting with governors," 10 Feb. 2020 So equities are more than holding their own during this uncertain period. Bernhard Warner, Fortune, "Multinationals see a new coronavirus red flag on the horizon—a stronger dollar," 10 Feb. 2020 But the site is now designated as a potential shelter for people from around the Caribbean in the event of a humanitarian disaster, leaving uncertain whether that part of the base will be available. Carol Rosenberg, New York Times, "With a Year Until Guantánamo’s 9/11 Trial, the Military Has a Long To-Do List," 9 Feb. 2020 And so the Embassy was discombobulated, disrupted, uncertain. Robin Wright, The New Yorker, "Ambassador Bill Taylor on Impeachment, Russia, and the Law of the Jungle," 8 Feb. 2020 The officers were forced to make a split-second decision in this tense, uncertain and rapidly evolving encounter. Robin Goist, cleveland, "Body-cam footage shows 19-year-old gesturing toward Akron officers seconds before being shot," 7 Feb. 2020

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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Time Traveler for uncertain

Time Traveler

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

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Last Updated

17 Feb 2020

Cite this Entry

“Uncertain.” Merriam-Webster.com Dictionary, Merriam-Webster, https://www.merriam-webster.com/dictionary/uncertain?pronunciation&lang=en_us&dir=u&file=uncert01. Accessed 23 Feb. 2020.

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More Definitions for uncertain


How to pronounce uncertain (audio)

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 How to pronounce uncertain (audio) \

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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