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.

Gorka can be remarkably candid and mercurial for a senior official with such a sensitive remit, according to hours of his public remarks reviewed by ProPublica.

From Salon • Apr. 22, 2026

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

From Barron's • Mar. 31, 2026

As Cassio, both Jake Roxander and Andrew Robare were notably cocky and mercurial.

From The Wall Street Journal • Mar. 18, 2026

In recent years, the mercurial superstar has faced a number of public and legal dramas.

From Los Angeles Times • Mar. 11, 2026

Kendra relished being part of the mercurial procession, overjoyed at the fortunate ending to the terrible night.

From "Fablehaven" by Brandon Mull

Vocabulary lists containing mercurial

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