mercurial

[mer-kyoor-ee-uhl] / mərˈkyʊər i əl /

ADJECTIVE

flighty, temperamental

Synonyms

STRONGEST

changeable effervescent erratic impulsive resilient unpredictable volatile

WEAK

blowing hot and cold bubbleheaded buoyant capricious elastic expansive fickle flaky flip fluctuating gaga gay inconstant irregular irrepressible lighthearted lively lubricious mad mobile movable quicksilver spirited sprightly ticklish unstable up-and-down variable yo-yo

Antonyms

STRONGEST

certain constant predictable reliable stable steady sure unchanging

WEAK

calm tranquil unchangeable unperturbable unvarying

Example Sentences

Examples are provided to illustrate real-world usage of words in context. Any opinions expressed do not reflect the views of Dictionary.com.

Your first chance to see whether mercurial French forward Kylian Mbappé, the world’s best player, is paying full attention this year.

From Salon • Jun. 11, 2026

But it will have its work cut out to placate the mercurial Republican.

From Barron's • Apr. 28, 2026

Master of the trivela, lover of a rabona - mercurial and erratic, but show-stoppingly skilful.

From BBC • Mar. 24, 2026

Isolde is a mercurial character, and Ms. Davidsen expressed her simmering rage, her girlish flirtatiousness, and her serenity in the “Liebestod.”

From The Wall Street Journal • Mar. 11, 2026

Her personality was too big and mercurial to be contained in a frail human body.

From "Darius the Great Is Not Okay" by Adib Khorram

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