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 In this still-early stage of the AI boom, Silicon Valley, for all its impunity, has chosen not to voice robust ideas about democracy that differ substantively from the whims of a mercurial White House. Matteo Wong, The Atlantic, 25 Aug. 2025 This is all the Phillies have ever wanted from their talented but mercurial double-play tandem, Stott and Trea Turner. Matt Gelb, New York Times, 21 Aug. 2025 And saying no to a quick deal that Trump supports, with thoughts of a Nobel Peace Prize within his grasp, could push the mercurial US president to lash out, perhaps cutting off crucial intelligence sharing again, or military aid. Matthew Chance, CNN Money, 18 Aug. 2025 But how much of your personality—a mercurial phenomenon—is deterministic, a set of probabilities that are no more inscrutable to algorithms than the arrangement of pieces on a chessboard? Webb Wright, Scientific American, 18 Aug. 2025 See All Example Sentences for mercurial
Recent Examples of Synonyms for mercurial
Adjective
  • CaSSIS, meanwhile, could provide insights into 3I/ATLAS' volatile activity and its composition.
    Andrew Jones, Space.com, 3 Sep. 2025
  • The film also chronicles the ups and downs of Kerr's volatile relationship with Dawn.
    Ashley Hume, FOXNews.com, 3 Sep. 2025
Adjective
  • Officials need to prepare for an unpredictable influx of people from a mass shooting.
    Eduardo Cuevas, USA Today, 29 Aug. 2025
  • Under his leadership at the civil rights commission, multiple former employees and contractors told IndyStar the environment felt hostile and unpredictable.
    Kayla Dwyer, IndyStar, 29 Aug. 2025

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Cite this Entry

“Mercurial.” Merriam-Webster.com Thesaurus, Merriam-Webster, https://www.merriam-webster.com/thesaurus/mercurial. Accessed 5 Sep. 2025.

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