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 Oil prices spiked and markets were broadly down on Friday as expectations for a full reopening of the strait looked increasingly uncertain. — semafor.com, 7 Aug. 2026 While the unanimous support from FDA advisors boded well for Moderna’s shot, the overall path to approval was treacherous and uncertain, even until the end. — Beth Mole, ArsTechnica, 6 Aug. 2026 On mobile devices and computers using USB-C video connections, though, HDR support is uncertain and inconsistent. — Will Greenwald, PC Magazine, 6 Aug. 2026 The broken line, the hard scar of the dash—these are gestures toward the uncertain and intractable distance between self and other, presence and absence, ‘awareness’ and its loss. — Literary Hub, 6 Aug. 2026 See All Example Sentences for uncertain

Recent Examples of Synonyms for uncertain

Adjective

Global oil prices have been volatile in recent weeks amid heightened uncertainty about potential outcomes from the Iran war.

— Sophie Tanno, CNN Money, 8 Aug. 2026
Those nitrogen oxides combine with volatile organic compounds on hot summer days, and the pollution contributes to climate change and harms human health.

— Noelle Phillips, Denver Post, 7 Aug. 2026

Definition of volatile

Adjective

During the flight, crews are in constant communication with meteorological teams across the globe to track unpredictable weather patterns.

— Diego Mendoza, CNN Money, 7 Aug. 2026
Within these spaces, designed to produce idealized performances of femininity, the unpredictable rhythms of postpartum life become a quiet act of disruption.

— Alessia Glaviano, Vogue, 7 Aug. 2026

Definition of unpredictable

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

Maybe someone noticed a person acting suspicious, heard a fight, saw someone leaving the area or remembers a detail that seemed insignificant at the time.

— Simcha Itzkowitz, New York Daily News, 12 Aug. 2026
CyberGuy's guide to protecting yourself from social media scammers includes more ways to evaluate suspicious accounts.

— Kurt Knutsson, FOXNews.com, 12 Aug. 2026

Definition of suspicious

Adjective

No one sees exactly what happened, and the only witness, a mentally unstable man, gives conflicting accounts that deepen the uncertainty.

— Georg Szalai, HollywoodReporter, 10 Aug. 2026
Events plod forward, one after the other, and although Michael Shaeffer is a thoroughly compelling presence as the cruel and chronically unstable monarch Aerys, other performances seem nuance-free.

— Andreas Wiseman, Deadline, 10 Aug. 2026

Definition of unstable

Adjective

Because the measures in the judge's order are specific to users in New Mexico, experts say piecemeal rulings and inconsistent legislation at the state level could create a new crop of issues.

— ABC News, ABC News, 8 Aug. 2026
The two regular season games against Chicago provided a microcosm of Nixon’s inconsistent season.

— Rob Reischel, Forbes.com, 8 Aug. 2026