Synonym Chooser

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 Jarecki hints that Assange can be his own worst enemy by displaying a mercurial temperament and superior attitude. Matthew Carey, Deadline, 21 May 2025 Actor Ncuti Gatwa's brief stint as the mercurial, time-traveling Doctor on the British series Doctor Who came to an end last Saturday. Glen Weldon, NPR, 7 June 2025 Given how mercurial Musk has proven to be, perhaps diversifying away from SpaceX isn’t a bad idea. Jeremy Bogaisky, Forbes.com, 6 June 2025 The more time spent on a personality clash between this pair of mercurial iconoclasts, the less time is being dedicated to getting Trump’s pending domestic agenda across the finish line. Philip Elliott, Time, 6 June 2025 See All Example Sentences for mercurial
Recent Examples of Synonyms for mercurial
Adjective
  • But make no mistake: the situation remains extremely volatile.
    Robert Rapier, Forbes.com, 16 June 2025
  • His aunt and two cousins traded stories about how volatile Williams was to even his own mother and the mother of his child.
    Colin Mixson, New York Daily News, 15 June 2025
Adjective
  • Each response is a surprise, tapping into the psychological principle of intermittent reinforcement, famously demonstrated by psychologist B.F. Skinner, where unpredictable rewards significantly amplify behaviors, much like gambling addiction.
    Curt Steinhorst, Forbes.com, 20 June 2025
  • Bright lights, unpredictable noises, unfamiliar smells, and the pressure to 'behave' in a certain way can quickly overwhelm a child whose brain processes the world differently.
    Jack Beresford, MSNBC Newsweek, 19 June 2025

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Cite this Entry

“Mercurial.” Merriam-Webster.com Thesaurus, Merriam-Webster, https://www.merriam-webster.com/thesaurus/mercurial. Accessed 30 Jun. 2025.

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