unstable

[uhn-stey-buhl] / ʌnˈsteɪ bəl /

ADJECTIVE

doubtful

Synonyms

STRONGEST

ambiguous changeable erratic fickle insecure irrational precarious risky rocky sensitive shaky slippery ticklish tricky uncertain unpredictable unsettled unsteady volatile weak wobbly

WEAK

borderline capricious dizzy dubious fitful fluctuating giddy inconsistent inconstant lubricious mercurial mobile movable moving mutable not fixed rickety shifty suspect teetering temperamental untrustworthy vacillating variable wavering weaving wiggly

Antonyms

STRONGEST

certain clear confident constant definite dependable easy firm guarded happy predictable protected reliable safe secure sound stable steady strong sure unchanging unshaky

Example Sentences

Examples are provided to illustrate real-world usage of words in context. Any opinions expressed do not reflect the views of Dictionary.com.

Communications had become very unstable in the city right from the beginning of the war because of the fighting, and because of a fuel shortage that cut the power.

From BBC • Apr. 14, 2026

Despite extreme heat, unstable conditions, and long-lasting droughts, Lystrosaurus not only endured but flourished.

From Science Daily • Apr. 14, 2026

Maybe she’s concerned that he could become financially unstable and a burden to her if he gives away too much.

From MarketWatch • Apr. 13, 2026

Even if the world’s governments manage to bring down carbon emissions in the next 25 years, scientists expect the climate to become much more unstable because of the damage that’s already been done.

From The Wall Street Journal • Apr. 6, 2026

When a neutron traveling at just the right speed strikes the nucleus of a uranium 235 atom, it is absorbed and the atom becomes even more unstable.

From "Meltdown" by Deirdre Langeland

Vocabulary lists containing unstable

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Engineering - Introductory

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