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.

Applegate in March released “You With the Sad Eyes,” detailing everything from her unstable childhood to her decades-spanning acting career and the health issues that have plagued it.

From Los Angeles Times • Apr. 20, 2026

By the time the doctor had logged there was no fetal heartbeat, the medical record shows, Crain was too unstable for surgery.

From Salon • Apr. 20, 2026

A Welsh Labour spokesperson said the party's vision was for an "energy‑independent Wales" to protect the country from "unstable global markets", adding it would ensure projects "benefit the communities that host them".

From BBC • Apr. 19, 2026

Interestingly, 12 of the 14 known circumbinary planets orbit just beyond this unstable region.

From Science Daily • Apr. 19, 2026

He spread this rumor that the school psychologist had told his mom that Jack was emotionally unstable.

From "Auggie & Me" by R. J. Palacio

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!