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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 Does your ankle wobble excessively or feel unstable? Dana Santas, CNN Money, 6 Nov. 2025 When these magnetic structures become unstable, the prominence can erupt, hurling plasma out into space. Daisy Dobrijevic, Space.com, 5 Nov. 2025 In 2022, four people fell from the same cliffside, one of whom died, prompting warnings from officials about unstable ground. Stepheny Price, FOXNews.com, 5 Nov. 2025 In addition to being constructed in a zone vulnerable to a major earthquake, the hospital sits in a low-lying plain just blocks from the waterfront, on unstable ground. Katia Riddle, NPR, 5 Nov. 2025 See All Example Sentences for unstable
Recent Examples of Synonyms for unstable
Adjective
  • Where Aytaç was large but poised, Abdi was insubstantial, scrawny, and unsteady on his feet.
    David Wingrave, Harpers Magazine, 24 Oct. 2025
  • If something feels unsteady or on shaky ground, it will be revealed — not to break you, but to rebuild something stronger.
    Valerie Mesa, PEOPLE, 22 Oct. 2025
Adjective
  • First, the electrodes and electrolytes are adjusted to handle high temperatures, specifically replacing the volatile liquid electrolyte used in traditional Li batteries.
    Mrigakshi Dixit, Interesting Engineering, 5 Nov. 2025
  • Taking the long view Many finance leaders remain cautious, viewing bitcoin as too volatile—especially recently—compared to traditional assets.
    Sheryl Estrada, Fortune, 4 Nov. 2025
Adjective
  • Jekalyn x The Legends arrives amid a precarious period for gospel music, especially considering five-time Grammy winner Chandler Moore’s bombshell exit from Maverick City Music and the top-selling group’s co-founder’s recent controversial comments.
    Kyle Denis, Billboard, 6 Nov. 2025
  • It’s been precarious the whole time.
    Zac Ntim, Deadline, 6 Nov. 2025
Adjective
  • This combination allows for precise navigation in tight or unpredictable environments.
    Aamir Khollam, Interesting Engineering, 7 Nov. 2025
  • Tinker was brilliant, unpredictable, and slightly unhinged.
    Henry Selick, IndieWire, 6 Nov. 2025
Adjective
  • Future work will focus on integrating snow-deposition modeling with PV yield simulations to more accurately predict energy losses and on expanding analyses to more complex, uneven alpine terrain.
    Jijo Malayil, Interesting Engineering, 8 Nov. 2025
  • The Trojans' uneven season hasn't exactly helped slow rumors either.
    Rowan Fisher-Shotton, MSNBC Newsweek, 8 Nov. 2025
Adjective
  • Frank Lloyd Wright’s Fallingwater (1937) remains the most famous example—a home literally suspended over a waterfall, designed in reverence to its rocky surroundings.
    Leonora Epstein, Architectural Digest, 7 Nov. 2025
  • However, the company has had a rocky year.
    Chris Isidore, CNN Money, 6 Nov. 2025
Adjective
  • 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
Adjective
  • This motion is typically caused when the unbalanced drum makes contact with the inside of the washing machine or when severe vibrations cause the machine to shift across the floor.
    Timothy Dale, Better Homes & Gardens, 6 Nov. 2025
  • That allows the president to impose tariffs of up to 15% for up to 150 days in response to unbalanced trade.
    Emma Burleigh, Fortune, 6 Nov. 2025

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Cite this Entry

“Unstable.” Merriam-Webster.com Thesaurus, Merriam-Webster, https://www.merriam-webster.com/thesaurus/unstable. Accessed 13 Nov. 2025.

More from Merriam-Webster on unstable

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