mercurial
- 1Often changing moods suddenly and without warning, or full of energy and quick to think.
My boss is mercurial, cheerful one minute and angry the next.
The singer's mercurial moods kept the whole band guessing.
UsageOften used with mood, temperament, or wit. It can show praise or criticism.
Similarunpredictable, fickle
Oppositestable, steady, placid
Note
- 2Containing mercury, the liquid silver metal, or having to do with it.
The lab keeps its mercurial compounds in a locked cabinet.
Doctors warned people not to buy mercurial skin creams online.
Note
- 3In astrology, having to do with the planet Mercury's effect on people, or having the nature it is said to give.
The astrologer said the baby was born under Mercury and would have a mercurial gift for words.
Astrologers say mercurial days are good for writing letters.
Note
Less common meanings
- 4Having to do with Mercury, the Roman god of trade, messages, and thieves. Also, sly or good at making money.
I know the ſhape of's Legge: this is his Hand: / His Foote Mercuriall: his martiall Thigh / The brawnes of Hercules: but his Iouiall face— / Murther in heaven?
1611, William Shakespeare, “The Tragedie of Cymbeline”Near-synonym: Hermesian
Note
- 5Having to do with the planet Mercury.
- 6In astrology, a person born under the planet Mercury, or someone clever, smooth-talking, sneaky, or moody.
- 7A chemical or medicine that contains mercury.
- 8Any plant of the kind called mercury, especially annual mercury.
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Origin
From Latin, from Mercurius, the Roman god Mercury. People born under the planet Mercury were once thought to be quick and changeable.
Checked 1 Nov 2026 · 2 facts
- Mercurial derives from Latin and ultimately from Mercurius, the Roman god Mercury. en.wiktionary.org
- People born under Mercury were formerly believed to be quick and changeable. en.wiktionary.org