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.

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

From Barron's • Apr. 28, 2026

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

They are, instead, lacunas to be reckoned with, stemming from the abiding obscurity of human psychology and deepened by the mercurial, ever-fading state of memory.

From The Wall Street Journal • Apr. 16, 2026

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

From BBC • Mar. 24, 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

The Vocabulary.com Top 1000

Looking to grow your vocabulary? Check out this interactive, curated word list from our team of English language specialists at Vocabulary.com – one of over 17,000 lists we've built to help learners worldwide!

The New SAT: Words to Capture Tone

Interested in learning more words like this one? Our team at Vocabulary.com has got you covered! You can review flashcards, quiz yourself, practice spelling, and more – and it's all completely free to use!

Did You Planet? Words With Surprisingly Spacey Origins

Want to remember this word for good? Start your learning journey today with our library of interactive, themed word lists built by the experts at Vocabulary.com – we'll help you make the most of your study time!