MERCURIAL Synonyms: 75 Similar and Opposite Words

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

Some common synonyms of mercurial are capricious , fickle , inconstant , and unstable . While all these words mean "lacking firmness or steadiness (as in purpose or devotion)," mercurial implies a rapid changeability in mood. // made anxious by her boss's mercurial temperament

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

The words capricious and mercurial can be used in similar contexts, but capricious suggests motivation by sudden whim or fancy and stresses unpredictability. // an utterly capricious critic

Q: When is 'fickle' a more appropriate choice than 'mercurial'?

While in some cases nearly identical to mercurial , fickle suggests unreliability because of perverse changeability and incapacity for steadfastness. // performers discover how fickle fans can be

Q: When is it sensible to use 'inconstant' instead of 'mercurial'?

The synonyms inconstant and mercurial are sometimes interchangeable, but inconstant implies an incapacity for steadiness and an inherent tendency to change. // an inconstant friend

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

Although the words unstable and mercurial have much in common, 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

mercurial

adjective

(ˌ)mər-ˈkyu̇r-ē-əl

Definition of mercurial

as in volatile

likely to change frequently, suddenly, or unexpectedly the boss's mood is so mercurial that we never know how he's going to react to anything

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How does the adjective mercurial differ from other similar words?

Some common synonyms of mercurial are capricious, fickle, inconstant, and unstable. While all these words mean "lacking firmness or steadiness (as in purpose or devotion)," mercurial implies a rapid changeability in mood.

made anxious by her boss's mercurial temperament

When could capricious be used to replace mercurial?

The words capricious and mercurial can be used in similar contexts, but capricious suggests motivation by sudden whim or fancy and stresses unpredictability.

an utterly capricious critic

When is fickle a more appropriate choice than mercurial?

While in some cases nearly identical to mercurial, fickle suggests unreliability because of perverse changeability and incapacity for steadfastness.

performers discover how fickle fans can be

When is it sensible to use inconstant instead of mercurial?

The synonyms inconstant and mercurial are sometimes interchangeable, but inconstant implies an incapacity for steadiness and an inherent tendency to change.

an inconstant friend

When would unstable be a good substitute for mercurial?

Although the words unstable and mercurial have much in common, 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

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 mercurial That mercurial flow of experience creates a sense of mental pace that’s in sharp counterpoint to the aesthetic style of the movie’s scenes. — Richard Brody, New Yorker, 11 Aug. 2026 The combination of pro wrestling and Brock Lesnar’s mercurial and unpredictable nature point to a universe where Brock Lesnar is more likely to come out of retirement than not. — Alfred Konuwa, Forbes.com, 4 Aug. 2026 Shifts in geopolitics, mercurial trade policies and evolving compliance requirements have been reshaping global sourcing, and the changes show no signs of letting up. — Arthur Zaczkiewicz, Footwear News, 3 Aug. 2026 The southernmost Scandinavian country might not seem like an obvious place to spend the warmer months—its mercurial weather is a far cry from the reliably balmy climes of Marseille or Sorrento. — Stephanie Gavan, Condé Nast Traveler, 31 July 2026 See All Example Sentences for mercurial

Recent Examples of Synonyms for mercurial

Adjective

Dado Ruvic | Reuters Bitcoin headed for its third straight winning week, as traders searched for refuge amid volatile moves in equities, currencies and bond markets.

— Liz Napolitano, CNBC, 4 Sep. 2026
That meant trade reporting on the tape often ran late, sometimes hours late during a volatile market or big sell-off.

— Brian Lund, Encyclopedia Britannica, 4 Sep. 2026

Definition of volatile

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“Mercurial.” Merriam-Webster.com Thesaurus, Merriam-Webster, https://www.merriam-webster.com/thesaurus/mercurial. Accessed 6 Sep. 2026.

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Synonyms of mercurial

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