Definition of unstablenext
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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 These foods work to curb cellular damage caused by free radicals, or unstable molecules that, in excess, can drive inflammation. Lauren Manaker, SELF, 26 Mar. 2026 But that number is based on a set of assumptions that seem to rest on increasingly unstable ground. Rebecca Noel, Charlotte Observer, 25 Mar. 2026 She’s also consumed by vengeful rage, much of it directed at the unstable assassin Bullseye (Wilson Bethel). Bob Strauss, Houston Chronicle, 25 Mar. 2026 She’s also consumed by vengeful rage, much of it directed at the unstable assassin Bullseye (Wilson Bethel). Bob Strauss, San Francisco Chronicle, 24 Mar. 2026 See All Example Sentences for unstable
Recent Examples of Synonyms for unstable
Adjective
  • Indoor environments also reduce the risk of falls or injuries, giving these unsteady felines the chance to adapt and live long, happy lives with a little extra patience and care.
    Liz O'Connell, MSNBC Newsweek, 30 Mar. 2026
  • As professionals try to navigate the unsteady road, the know-how and expertise of film commissions will become even more valuable.
    Rafa Sales Ross, Variety, 23 Mar. 2026
Adjective
  • The comparison isn't perfect — stock data spans decades, while trends in trading card values are shorter and more volatile — but the outperformance in certain windows is still striking.
    Brandon Gomez, CNBC, 29 Mar. 2026
  • These volatile, double-digit voting shifts directly contrast more stable voting patterns among other major demographic groups, including the Black and white electorates, where shifts from cycle to cycle tend to be just a few points.
    Los Angeles Times, Los Angeles Times, 29 Mar. 2026
Adjective
  • In some studies, gloves not changed between tasks had higher bacterial counts and could transfer germs just as easily as ungloved hands, underscoring the need for frequent changing and proper hand hygiene.
    Evan Moore December 19, Charlotte Observer, 19 Dec. 2025
Adjective
  • This shift is already underway, suggesting a precarious future across television.
    Alison Foreman, IndieWire, 25 Mar. 2026
  • The gas price spike comes with many consumers already in a precarious position, particularly compared to 2022, when gas prices also soared because of Russia’s invasion of Ukraine.
    Christopher Rugaber, Fortune, 23 Mar. 2026
Adjective
  • Prices are subject to rapid, unpredictable changes due to factors like, but not limited to, supply/demand, weather, and geopolitical events.
    USA TODAY, USA Today, 31 Mar. 2026
  • Air travelers are paying the price of the shutdown with unpredictable, snaking TSA lines at airports across the country, jeopardizing their chances to pass through security on time for their flights.
    Graham Hurley, CNN Money, 31 Mar. 2026
Adjective
  • So while ending as a positive, the unit’s minutes were uneven.
    Anthony Chiang, Miami Herald, 26 Mar. 2026
  • Sound waves ricocheting between buildings stretched out reverberation times and created an uneven acoustic field.
    Yook JiHun, Popular Science, 26 Mar. 2026
Adjective
  • That cliffhanger leads into what will be a tragic finale, opening up with the ‘90s power couple finding themselves in a rocky place, as was teased in the flash-forward first moments of the premiere.
    Lexi Carson, HollywoodReporter, 25 Mar. 2026
  • Their Extract Mode let drivers raise the truck an additional six inches for rocky terrain.
    Jon McNeill, Big Think, 25 Mar. 2026
Adjective
  • This is a recurring injury for Smith, who has missed five of the last nine games due to varying levels of discomfort in his calf.
    Julia Poe, Chicago Tribune, 23 Feb. 2026
  • Even within a single day, temporary weight shifts are common and are often due to varying levels of fluid retention.
    Lauren O'Connor, Health, 22 Oct. 2025

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Cite this Entry

“Unstable.” Merriam-Webster.com Thesaurus, Merriam-Webster, https://www.merriam-webster.com/thesaurus/unstable. Accessed 1 Apr. 2026.

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