Definitions

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

President Donald Trump has a notably mercurial personality.

From BBC • Apr. 28, 2026

He certainly managed differently than the more mercurial Jobs, setting a kinder, gentler tone.

From The Wall Street Journal • Apr. 21, 2026

The mercurial striker last played for his country in October 2023.

From Barron's • Mar. 31, 2026

Ac-cording to members of the extended family, his moods can be dark and mercurial, although they say his famous temper has lost much of its volatility in recent years.

From "Into the Wild" by Jon Krakauer

Vocabulary lists containing mercurial

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