UNSTABLE Synonyms: 115 Similar and Opposite Words

Q: How does the adjective 'unstable' differ from other similar words?

Some common synonyms of unstable are capricious , fickle , inconstant , and mercurial . While all these words mean "lacking firmness or steadiness (as in purpose or devotion)," unstable implies an incapacity for remaining in a fixed position or steady course and applies especially to a lack of emotional balance. // too unstable to hold a job

Q: When can 'capricious' be used instead of 'unstable'?

The synonyms capricious and unstable are sometimes interchangeable, but capricious suggests motivation by sudden whim or fancy and stresses unpredictability. // an utterly capricious critic

Q: When would 'fickle' be a good substitute for 'unstable'?

The words fickle and unstable can be used in similar contexts, but fickle suggests unreliability because of perverse changeability and incapacity for steadfastness. // performers discover how fickle fans can be

Q: When is 'inconstant' a more appropriate choice than 'unstable'?

The words inconstant and unstable are synonyms, but do differ in nuance. Specifically, inconstant implies an incapacity for steadiness and an inherent tendency to change. // an inconstant friend

Q: When could 'mercurial' be used to replace 'unstable'?

Although the words mercurial and unstable have much in common, mercurial implies a rapid changeability in mood. // made anxious by her boss's mercurial temperament

unstable

adjective

ˌən-ˈstā-bəl

Definition of unstable next

as in unsteady

not being in or able to maintain a state of balance the minute we put the books down on the unstable desk, the whole stack went crashing to the floor

Synonyms & Similar Words

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Antonyms & Near Antonyms

as in volatile

likely to change frequently, suddenly, or unexpectedly financial investors don't like an unstable economy

Synonyms & Similar Words

Antonyms & Near Antonyms

as in changing

not staying constant unstable temperatures are not ideal storage conditions for wine

Synonyms & Similar Words

Antonyms & Near Antonyms

Synonym Chooser

How does the adjective unstable differ from other similar words?

Some common synonyms of unstable are capricious, fickle, inconstant, and mercurial. While all these words mean "lacking firmness or steadiness (as in purpose or devotion)," unstable implies an incapacity for remaining in a fixed position or steady course and applies especially to a lack of emotional balance.

too unstable to hold a job

When can capricious be used instead of unstable?

The synonyms capricious and unstable are sometimes interchangeable, but capricious suggests motivation by sudden whim or fancy and stresses unpredictability.

an utterly capricious critic

When would fickle be a good substitute for unstable?

The words fickle and unstable can be used in similar contexts, but fickle suggests unreliability because of perverse changeability and incapacity for steadfastness.

performers discover how fickle fans can be

When is inconstant a more appropriate choice than unstable?

The words inconstant and unstable are synonyms, but do differ in nuance. Specifically, inconstant implies an incapacity for steadiness and an inherent tendency to change.

an inconstant friend

When could mercurial be used to replace unstable?

Although the words mercurial and unstable have much in common, mercurial implies a rapid changeability in mood.

made anxious by her boss's mercurial temperament

Example Sentences

Examples are automatically compiled from online sources to show current usage. Read More Opinions expressed in the examples do not represent those of Merriam-Webster or its editors. Send us feedback.

Recent Examples of unstable After a tough and unstable upbringing in Chicago, Parks, now 46, joined the Marine Corps in 2005, then was deployed to Iraq. —

Meredith Colias-Pete, Chicago Tribune, 31 Jan. 2025 Active weather, including significant snowfall and winds, could make these layers unstable. —

Dan Perry, Newsweek, 31 Jan. 2025 Emergency crews battled unstable ground and debris. —

Anthony Trotter, ABC News, 28 Jan. 2025 Some predict that if economic and political conditions remain unstable, gold could continue to rise. —

Quartz Intelligence Newsroom, Quartz, 1 Feb. 2025 See all Example Sentences for unstable

Recent Examples of Synonyms for unstable

Adjective

As an aerodynamics engineer specializing in aeroelastic and unsteady flows, Atlee provided key technical contributions to the original F-16 design that helped define the way that jet looks and flies.

— Shambhavi Rimal, Fort Worth Star-Telegram, 7 Feb. 2025
Most places extending radical hospitality are doing it out of pocket or through an unsteady stream of donations, and the truth is: No one can afford it.

— Tejal Rao, New York Times, 18 Jan. 2025