uncertain

adjective

un·​cer·​tain ˌən-ˈsər-tᵊn How to pronounce uncertain (audio)
Synonyms of uncertainnext
1
a
: 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
uncertainly adverb
uncertainness
ˌən-ˈsər-tᵊn-(n)əs How to pronounce uncertain (audio)
noun

Synonyms of uncertain

Relevance
See All Synonyms & Antonyms in Thesaurus

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.
Recent Examples on the Web
Examples are automatically compiled from online sources to show current usage. Read More Opinions expressed in the examples do not represent those of Merriam-Webster or its editors. Send us feedback.
In uncertain environments, a single governing objective plus constraints felt simpler than genuine multi-objective balancing. — Steve Denning, Forbes.com, 3 Aug. 2026 The trade came at an uncertain time for the Tigers, who have overcome a slow start to the season to get close to playoff position. — ABC News, 2 Aug. 2026 Building a budget around uncertain money could deter lenders, officials said, threatening the district’s ability to secure short-term borrowing and make payroll. — Kate Armanini, Chicago Tribune, 1 Aug. 2026 As if this wasn’t a bad enough start to the year, he was soon dropped by his team and faced an uncertain future — all as reigning Tour de France champion. — Tom Campbell, New York Times, 1 Aug. 2026 See All Example Sentences for uncertain

Word History

First Known Use

14th century, in the meaning defined at sense 3

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

Phrases Containing uncertain

Rhymes for uncertain

See All Rhymes for uncertain

Browse Nearby Words

unceremonious
uncertain
uncertainty
See all Nearby Words

Cite this Entry

“Uncertain.” Merriam-Webster.com Dictionary, Merriam-Webster, https://www.merriam-webster.com/dictionary/uncertain. Accessed 5 Aug. 2026.

Copy Citation

Kids Definition

uncertain

adjective
un·​cer·​tain ˌən-ˈsərt-ᵊn How to pronounce uncertain (audio)
ˈən-
1
: not definite or fixed
an uncertain quantity
2
a
: not sure
uncertain of the truth
b
: not known for sure
an uncertain claim
3
: likely to change : not dependable
uncertain weather
uncertainly adverb

More from Merriam-Webster on uncertain

Nglish: Translation of uncertain for Spanish Speakers

Last Updated: - Updated example sentences
Love words? Need even more definitions?

Subscribe to America's largest dictionary and get thousands more definitions and advanced search—ad free!

Popular in Grammar & Usage

See More

7 Pairs of Commonly Confused Words

Merriam-Webster’s Great Big List of Words You Love to Hate

Is it 'nerve-racking' or 'nerve-wracking'?

'Sneaked' or 'Snuck': Which is correct?

Why does English have so many silent letters?
See More

Popular in Wordplay

See More

Dutch Treat and French Leave: Eight Place-Based Compounds

14 Phobias You Probably Haven't Heard Of

The Longest Long Words List

How long is a jiffy?

Even More Bird Names that Sound Like Insults (and Sometimes Are)
See More

Popular

See More

7 Pairs of Commonly Confused Words

Dutch Treat and French Leave: Eight Place-Based Compounds

14 Phobias You Probably Haven't Heard Of
See More

Games & Quizzes

See All
Play Quordle: Guess all four words in a limited number of tries. Each of your guesses must be a real 5-letter word.
Quordle Can you solve 4 words at once?
Play Blossom: Solve today's spelling word game by finding as many words as you can using just 7 letters. Longer words score more points.
Blossom Pick the best words!
Play Missing Letter: a crossword with a twist. Each of the 25 puzzle words start with a different letter of the alphabet. Which letter is missing?
The Missing Letter A daily crossword with a twist
asap street sign
Figure Out These Acronyms ASAP You don't have to be a NASA engineer to get these...
See All