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.

They were more resistant to drying out, which would have been crucial in the dry and unstable climate following the mass extinction.

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

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

From The Wall Street Journal • Apr. 1, 2026

Researchers found that Latino students faced myriad challenges, including immigration issues, English proficiency and unstable housing that is linked to their parents’ employment status.

From Los Angeles Times • Apr. 1, 2026

They become unstable and have a tendency to unsettle the mood because they deviate from comfortable convention, seeking relationships with unfamiliar chords.

From "The Story of Music" by Howard Goodall

Vocabulary lists containing unstable

100 SAT Words Beginning with "U"

Looking to grow your vocabulary? Check out this interactive, curated word list from our team of English language specialists at Vocabulary.com – one of over 17,000 lists we've built to help learners worldwide!

Engineering - Introductory

Interested in learning more words like this one? Our team at Vocabulary.com has got you covered! You can review flashcards, quiz yourself, practice spelling, and more – and it's all completely free to use!

Civil Engineering

Want to remember this word for good? Start your learning journey today with our library of interactive, themed word lists built by the experts at Vocabulary.com – we'll help you make the most of your study time!