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 next

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 The volunteer, named Jacki and played with warm restraint by Tessa Thompson, has been slowly developing a friendship with Yarris, a mercurial but undeniably charismatic character played by Adrien Brody, your go-to actor for any slight man with a loping, unsteady energy. —

Jackson McHenry, Vulture, 16 Apr. 2026 Quiet Maryam and mercurial Farhan—eight years apart—had often squabbled, gone through periods of not talking, but without her sister as a foil, Maryam was diminished. —

Danielle Parker, CBS News, 14 Apr. 2026 What should be a straightforward day of music grinds to a halt as the artists struggle to deal with personality clashes, an ambitious trumpeter named Levee (Boseman), and the band's mercurial frontwoman. —

James Mercadante, Entertainment Weekly, 12 Apr. 2026 The award for most mercurial, though? —

Brittany Allen, Literary Hub, 10 Apr. 2026 See All Example Sentences for mercurial

Recent Examples of Synonyms for mercurial

Adjective

Demand rises, infrastructure costs increase, and households remain exposed to volatile energy prices.

— Ed Gaskin, Boston Herald, 26 Apr. 2026
Traders on the prediction market site Polymarket were giving Musk 32% odds of success as of Friday, after weeks of volatile price swings.

— David Ingram, NBC news, 26 Apr. 2026

Definition of volatile

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“Mercurial.” Merriam-Webster.com Thesaurus, Merriam-Webster, https://www.merriam-webster.com/thesaurus/mercurial. Accessed 1 May. 2026.

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Synonyms of mercurial

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