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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 Many uber-thick soles are also just plain unstable. Jennifer Heimlich, SELF, 30 July 2025 We are beset by panhandlers, shouted at by unstable wanderers, and forced to abandon our own plans to the claims of others who have made public places theirs exclusively. Thomas G. Moukawsher, MSNBC Newsweek, 29 July 2025 In rivers like the Mississippi, sandbars can be unstable and collapse under weight or shifting currents. Michael Dorgan, FOXNews.com, 24 July 2025 And the economy, right now, feels unstable to many, as grocery prices rise and the job market goes on a diet. Sophie Levenson, Chicago Tribune, 20 July 2025 See All Example Sentences for unstable
Recent Examples of Synonyms for unstable
Adjective
  • At the scene, Durham appeared to be unsteady on his feet, slurred his speech and had dilated pupils, according to an arrest affidavit.
    Brad Schmitt, The Tennessean, 16 July 2025
  • As seen in a video shared on social media by royal reporter Rhiannon Mills of Sky News, William also admitted that his device was unsteady.
    Stephanie Petit, People.com, 22 May 2025
Adjective
  • The consequences would be far reaching and upend an already volatile political world.
    Michael Smolens, San Diego Union-Tribune, 3 Aug. 2025
  • The explosion was one of the country’s largest since the 2010 eruption of Mount Merapi, the country’s most volatile volcano.
    Rachel Wolf, FOXNews.com, 2 Aug. 2025
Adjective
  • The time from when the patient arrives in the operating room to the time the patient is able to be on the heart-lung bypass machine is the most precarious.
    Nicole Villalpando, Austin American Statesman, 30 July 2025
  • In a precarious spot, the success of Borderlands 4 will ride on regaining some of its old magic.
    Jonathan Zavaleta, Rolling Stone, 25 July 2025
Adjective
  • Unlike cheaper rebounders that can feel stiff or unpredictable, this one stays sturdy and responsive.
    Jordan Galloway, SELF, 15 July 2025
  • Not pleased by the unpredictable nature of MP stock?
    Trefis Team, Forbes.com, 14 July 2025
Adjective
  • With a single subwoofer, the frequency response can be uneven because of peaks and dips in certain frequency ranges.
    Mark Sparrow, Forbes.com, 3 Aug. 2025
  • And this uneven, sometimes sloppy vehicle gets a real boost from Method Man.
    Dennis Harvey, Variety, 1 Aug. 2025
Adjective
  • Actor and director Erich von Stroheim, who was cast as Desmond’s worshipful valet, driver and former silent film director, had a rocky history with Swanson.
    Scott Huver, People.com, 3 Aug. 2025
  • A lot has changed in the nearly eight years since then, including the Russian invasion of Ukraine, the rocky departure of Roscosmos leader Dmitry Rogozin in 2022 who was subsequently dispatched to the front lines of the war, several changes in NASA leadership, and more.
    Eric Berger, ArsTechnica, 1 Aug. 2025
Adjective
  • Adding McMahon makes the Yankees a bit unbalanced in lineup handedness, something Boone obsesses over.
    Chris Kirschner, New York Times, 26 July 2025
  • Officials in Brussels are prepared to stomach an unbalanced agreement that favors the US if that’s what is required to break the impasse before the deadline.
    Sydney Lake, Fortune, 21 July 2025

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Cite this Entry

“Unstable.” Merriam-Webster.com Thesaurus, Merriam-Webster, https://www.merriam-webster.com/thesaurus/unstable. Accessed 6 Aug. 2025.

More from Merriam-Webster on unstable

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