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.

The researchers believe the shipment sank during a particularly unstable period in Mediterranean history.

From Science Daily • Jun. 8, 2026

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

At the heart of quantum computing are qubits, which offer the promise of answering questions that defeat today's machines, but are notoriously delicate and unstable.

From BBC • Jun. 2, 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

I’m unstable almost immediately and begin to fall backward.

From "Everything, Everything" by Nicola Yoon

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!