Definitions

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.

But over the short and even intermediate terms, lasting not just several years but decades, gold’s correlation to inflation is unstable.

From MarketWatch • Jun. 8, 2026

Earthquakes are common in the Philippines, which sits on the geologically unstable "ring of fire".

From BBC • Jun. 8, 2026

Born in Los Angeles on June 1, 1926, Monroe had an unstable childhood spent between orphanages and foster homes.

From Barron's • Jun. 1, 2026

Because these intermediate phases are highly unstable, they have been extremely difficult to observe directly.

From Science Daily • May 30, 2026

“Sorry, it’s all I’ve got. Anyway, potassium chlorate is unstable under heat and pressure. It's too dangerous for rocket fuel. What do your parents think about the BCMA?”

From "October Sky" by Homer Hickam

Vocabulary lists containing unstable

100 SAT Words Beginning with "U"

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Engineering - Introductory

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Civil Engineering

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