UNCERTAIN Synonyms: 104 Similar and Opposite Words

uncertain

adjective

ˌən-ˈsər-tᵊn

Definition of uncertain

as in volatile

likely to change frequently, suddenly, or unexpectedly the stifling heat would occasionally be relieved by an uncertain breeze

Synonyms & Similar Words

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Antonyms & Near Antonyms

as in unsure

not feeling sure about the truth, wisdom, or trustworthiness of someone or something never uncertain of her political beliefs or judgment, she was a decisive and fearless leader

Synonyms & Similar Words

Antonyms & Near Antonyms

Example Sentences

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.

Recent Examples of uncertain Their biological purpose remains uncertain despite decades of investigation. — Aamir Khollam, Interesting Engineering, 4 Nov. 2026 The risk, in short, is too high to take for uncertain returns. — Tom Moerenhout, Foreign Affairs, 4 Nov. 2026 As a first-of-its-kind wealth tax, the measure also risks uncertain consequences, such as legal challenges, some opponents note. — ABC News, 3 Nov. 2026 What Tuesday could mean Whether Cabarrus’ changing electorate translates into Democratic legislative victories remains uncertain. — Charlotte Observer, 3 Nov. 2026 See All Example Sentences for uncertain

Recent Examples of Synonyms for uncertain

Adjective

The war has cast a shadow on Persian Gulf nations that have long presented themselves as paragons of stability in a volatile region, mostly unaffected by the conflicts raging in the wider Middle East.

— Nabih Bulos, Los Angeles Times, 4 Nov. 2026
Daco recommends testing investments against a range of financing costs and maintaining hurdle rates that reflect a structurally higher and more volatile cost of capital.

— Sheryl Estrada, Fortune, 4 Nov. 2026

Definition of volatile

Adjective

Omer Shamir France Fleeing from Khan Younis, award-winning Palestinian photojournalist Mohammed Zaanoun moves his immediate family to safety in Egypt, unsure of what’s to come.

— Georg Szalai, HollywoodReporter, 29 Oct. 2026
DiCamillo said backers of a ballot measure also should be concerned any time support registers below 50%, since voters who are undecided or unsure tend to vote no.

— Seema Mehta, Los Angeles Times, 29 Oct. 2026

Definition of unsure

Adjective

Climbing precarious and unpredictable steps really tests some important mechanics as the technology develops – including balance, real-time decision-making and adaptation.

— New Atlas, New Atlas, 4 Nov. 2026
The tightest, most unpredictable race in Illinois this year may actually be the race for Chicago School Board President.

— CBS News, CBS News, 3 Nov. 2026

Definition of unpredictable

Adjective

Ivan, the younger son, is doubtful and skeptical of his father, whereas Andrey, the elder, is faithful and trusting—the twin archetypes of man’s relation to the divine.

— Joshua Yaffa, New Yorker, 2 Nov. 2026
He has been joined in recent years by tax-skeptical scholars at the Manhattan Institute and Tax Foundation.

— M. Nolan Gray, Washington Post, 2 Nov. 2026

Definition of skeptical

Adjective

Rigorous, blustery winter; winding sleety spring; hot, moist enervating summer; changeful autumn with its dog-days; these are absolutely unknown.

— San Diego Union-Tribune, San Diego Union-Tribune, 1 Jan. 2023
Hers is the kind of face that inspires directors to tight framing — gleaming, as if smoothed from marble, and yet somehow pliant, changeful.

— Jordan Kisner Jack Davison, New York Times, 11 Oct. 2022

Definition of changeful

Adjective

Water essentially acts as a catalyst that spontaneously creates particles known as hydroxyl radicals, unstable molecules linked to aging and disease.

— Michael Hawthorne, Chicago Tribune, 22 Oct. 2026
If a tree appears diseased, unstable or at risk of falling, consider documenting the problem and notifying the owner in writing.

— Sacbee.com, Sacbee.com, 22 Oct. 2026

Definition of unstable

Adjective

Lucy’s behavior may be frustratingly inconsistent, but many viewers will recognize the immeasurable suffering that drives it.

— Los Angeles Times, Los Angeles Times, 30 Oct. 2026
That triggers First Amendment protection, and that means there cannot be viewpoint discrimination or unreasonable restrictions that are inconsistent with the speech activities imposed on the journalists.

— Ted Johnson, Deadline, 30 Oct. 2026