mercurial

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adjective

mer·cu·ri·al (ˌ)mər-ˈkyu̇r-ē-əl

: of, relating to, or born under the planet Mercury

: having qualities of eloquence, ingenuity, or thievishness attributed to the god Mercury or to the influence of the planet Mercury

: characterized by rapid and unpredictable changeableness of mood

a mercurial temper

: of, relating to, containing, or caused by mercury

mercurially

(ˌ)mər-ˈkyu̇r-ē-ə-lē

adverb

mercurialness noun

mercurial

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noun

: a pharmaceutical or chemical containing mercury

Choose the Right Synonym for mercurial

inconstant, fickle, capricious, mercurial, unstable mean lacking firmness or steadiness (as in purpose or devotion).

inconstant implies an incapacity for steadiness and an inherent tendency to change.

an inconstant friend

fickle suggests unreliability because of perverse changeability and incapacity for steadfastness.

performers discover how fickle fans can be

capricious suggests motivation by sudden whim or fancy and stresses unpredictability.

an utterly capricious critic

mercurial implies a rapid changeability in mood.

made anxious by her boss's mercurial temperament

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

Adjective Few moments in English history have been more hungry for the future, its mercurial possibilities and its hope of richness, than the spring of 1603.

Adam Nicolson, God's Secretaries, 2003 Though you could see all three places in one day, each of them makes you want to stay or to keep returning to watch the effects of the changing weather and the mercurial Sicilian light.

Francine Prose, Atlantic, December 2002 Some scientists suggest that because manic-depressive patients are ever riding the bio-chemical express between emotional extremes, their brains end up more complexly wired and remain more persistently plastic than do the brains of less mercurial sorts.

Natalie Angier, New York Times, 12 Oct. 1993 Still grinning, still miming, he samba-ed across the floor … and started in on the dishes with a vigor that would have prostrated his mercurial cousin.

T. Coraghessan Boyle, Harper's, October 1987 the boss's mood is so mercurial that we never know how he's going to react to anything

Recent Examples on the Web

Adjective

Since that Friday in October, Musk’s brief reign at Twitter has been marked by chaos and upheaval as the notoriously mercurial and impatient billionaire seeks to impose his will on a company famous for its deliberative culture.

Cat Zakrzewski, Faiz Siddiqui, Joseph Menn, Anchorage Daily News, 22 Nov. 2022 Since that Friday in October, Musk’s brief reign at Twitter has been marked by chaos and upheaval as the notoriously mercurial and impatient billionaire seeks to impose his will on a company famous for its deliberative culture.

Joseph Menn, Washington Post, 18 Nov. 2022 Elon Musk, the mercurial billionaire, had agreed to buy Twitter for $44 billion the month before only to begin raising doubts about the deal soon after.

Seth Fiegerman, CNN, 29 Oct. 2022 The performance that results is assured, mercurial and physical.

Jordan Kisner Jack Davison, New York Times, 11 Oct. 2022 Jamie is mercurial in the way everybody in Mammals wants to be or, by laws of nature, should be.

Daniel Fienberg, The Hollywood Reporter, 10 Nov. 2022 News that the mercurial CEO personally acquired a 9% stake in the social media company coincided with the stock’s most recent peak at around $1,145 in April.

Christiaan Hetzner, Fortune, 19 July 2022 Industry analysts are skeptical about whether the mercurial CEO will remain on the sidelines for long.

Michelle Chapman And Tom Krisher, Anchorage Daily News, 4 Apr. 2022 Ukraine should not be dependent on a system so subject to one man’s infamously mercurial whims.

WIRED, 21 Oct. 2022 See More

These example sentences are selected automatically from various online news sources to reflect current usage of the word 'mercurial.' Views expressed in the examples do not represent the opinion of Merriam-Webster or its editors. Send us feedback.