mercurial

[ mer-kyoor-ee-uhl ]

adjective

1. changeable; volatile; fickle; flighty; erratic:

   a mercurial nature.

   Synonyms: indecisive, inconstant

   Antonyms: steady, constant

2. animated; lively; sprightly; quick-witted.

   Synonyms: spirited

   Antonyms: phlegmatic

3. pertaining to, containing, or caused by the metal mercury.
4. (initial capital letter) of or relating to the god Mercury.
5. (initial capital letter) of or relating to the planet Mercury.

noun

1. Pharmacology. a preparation of mercury used as a drug.

mercurial

/ mɜːˈkjʊərɪəl /

adjective

1. of, like, containing, or relating to mercury
2. volatile; lively

   a mercurial temperament

3. sometimes capital of, like, or relating to the god or the planet Mercury

noun

1. med any salt of mercury for use as a medicine

Derived Forms

• merˈcurially, adverb
• merˈcurialness, noun

Other Words From

• mer·curi·al·ly adverb
• mer·curi·al·ness mer·curi·ali·ty noun
• unmer·curi·al adjective
• unmer·curi·al·ly adverb
• unmer·curi·al·ness noun

Word History and Origins

Origin of mercurial¹

First recorded in 1350–1400; Middle English, from Latin mercuriālis “of or pertaining to the god or planet Mercury”; mercury, -al ¹

Word History and Origins

Origin of mercurial¹

C14: from Latin mercuriālis

Example Sentences

City officials expressed fear that Trump, a mercurial leader prone to grudges, would retaliate against California and Los Angeles because of its Democratic leadership.

From Los Angeles Times

World leaders swiftly weighed in, ranging from enthusiastic congratulations to more somber and circumspect assurances of continuity in the relationship with Trump, whose mercurial first presidency upended many longstanding diplomatic norms.

From Los Angeles Times

In Taiwan, where many supported Trump in 2020 for his tough-on-China stance, some people have since grown wary of the former president’s mercurial approach to foreign policy.

From Los Angeles Times

Beijing’s “stringent yet mercurial responses” during the pandemic have heightened people’s insecurity about the future.

From BBC

The mercurial forces that condition life for the creatures of the Earth’s surface — sunlight, winds, the seasons, the weather — have little reach into the deep-sea ecosystem.

From Salon

Related Words

• changeable
• effervescent
• erratic
• impulsive
• resilient
• unpredictable
• volatile