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 Trump in turn deputized Musk to lead a sweeping effort to slash government spending and reshape the federal bureaucracy before the mercurial billionaire stepped back from that role last week. Bloomberg, Mercury News, 6 June 2025 The investment required to get a battery recycling operation up and running is substantial, and the revenue stream for U.S. automakers is difficult to project due to the mercurial changes facing the EV environment in North America. Jackie Charniga, USA Today, 22 July 2025 Quaid and Barr are also known to share highly mercurial personalities. Brian Niemietz, New York Daily News, 22 July 2025 The next president, or even the current one should his notoriously mercurial mood change, could effectively bankrupt them all. Nicholas Creel, MSNBC Newsweek, 16 July 2025 See All Example Sentences for mercurial
Recent Examples of Synonyms for mercurial
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 best time for aurora spotting is 2 am, when the sky is likely to be the darkest, but since the arrival of the solar storm is unpredictable, it's recommended to look throughout the night for the event.
    Staff Author, Travel + Leisure, 7 Aug. 2025
  • Renewables may be homegrown, but their output is inherently unpredictable.
    Andrew Saunders, Fortune, 5 Aug. 2025

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Cite this Entry

“Mercurial.” Merriam-Webster.com Thesaurus, Merriam-Webster, https://www.merriam-webster.com/thesaurus/mercurial. Accessed 15 Aug. 2025.

More from Merriam-Webster on mercurial

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