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.

When that happens, the planet's orbit becomes stretched and unstable.

From Science Daily • Apr. 19, 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

"Rivers that are normally completely frozen have overflowed where they hadn't historically," he told the BBC, causing layered, unstable ice sheets that are hazardous to travel over in winter months.

From BBC • Apr. 12, 2026

Rising temperatures are making these walls, called moraines, increasingly unstable.

From The Wall Street Journal • Apr. 1, 2026

Such combinations make up the particles known as mesons, which are unstable because the quark and antiquark can annihilate each other, producing electrons and other particles.

From "A Brief History of Time: And Other Essays" by Stephen Hawking

Vocabulary lists containing unstable

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Engineering - Introductory

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