mer·cu·ri·al
(ˌ)mər-ˈkyu̇r-ē-əl 
1
: of, relating to, or born under the planet Mercury
2
: having qualities of eloquence, ingenuity, or thievishness attributed to the god Mercury or to the influence of the planet Mercury
3
: characterized by rapid and unpredictable changeableness of mood
a mercurial temper
4
: of, relating to, containing, or caused by mercury
mercurialness
noun
: a pharmaceutical or chemical containing mercury
Did you know?
The Roman god Mercury was the messenger and herald of the gods and also the god of merchants and thieves (his counterpart in Greek mythology is Hermes). He was noted for his eloquence, swiftness, and cunning, and the Romans named what appeared to them to be the fastest-moving planet in his honor. Mercurial comes from the Latin adjective mercurialis, meaning "of or relating to Mercury."
Synonyms
Examples of mercurial in a Sentence
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
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
Joshua Rivera, Vulture, 13 Nov. 2024
The mercurial population of the District of Columbia, with 8.48% of residents being newcomers.
—Jonathan Lansner, Orange County Register, 11 Nov. 2024
Brian Truitt, USA TODAY, 16 Aug. 2024
See all Example Sentences for mercurial 
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Adjective
Batman’s comedic Technicolor stylings — and the utter sincerity with which stars Adam West and Burt Ward led viewers through them — have lived on through countless references and parodies in the ensuing decades, as well as a mercurial relationship with Batman fans.
—Joshua Rivera, Vulture, 13 Nov. 2024
The mercurial population of the District of Columbia, with 8.48% of residents being newcomers.
—Jonathan Lansner, Orange County Register, 11 Nov. 2024
Noun
Austin Butler is the wild-at-heart troublemaker, Jodie Comer is his worried girlfriend, but Tom Hardy shines as the bikers' mercurial, Brando-esque leader.
—Brian Truitt, USA TODAY, 16 Aug. 2024
See all Example Sentences for mercurial
Dictionary Entries Near mercurial
Cite this Entry
“Mercurial.” Merriam-Webster.com Dictionary, Merriam-Webster, https://www.merriam-webster.com/dictionary/mercurial. Accessed 30 Nov. 2024.
Copy CitationMedical Definition
mercurial
1 of 2 adjective
mer·cu·ri·al
(ˌ)mər-ˈkyu̇r-ē-əl
: of, relating to, containing, or caused by mercury
mercurial salves
mercurial
2 of 2 noun
: a pharmaceutical or chemical containing mercury
the diuretic action of mercurials
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