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mercurial

mer·cu·ri·al/mɝˈkjʊ.ɹi.əl/noun, adjective

mercurial is a noun meaning “A person born under the influence of the planet Mercury; hence, a person having an eloquent, quickwitted, furtive, or volatile character” (English Wiktionary, September 2026). It is spelled M-E-R-C-U-R-I-A-L and has 4 syllables (mer·cu·ri·al), and it appears about once in every 2 million words in written English (wordfreq, 2021 data). The plural of mercurial is mercurials.

What does mercurial mean?

noun

  1. 1

    obsoleteAny of the plants known as mercury, especially the annual mercury or French mercury (Mercurialis annua).

  2. 2

    A person born under the influence of the planet Mercury; hence, a person having an eloquent, quickwitted, furtive, or volatile character.

  3. 3

    A chemical compound containing mercury.

  4. 4

    A preparation of mercury, especially as a treatment for syphilis.

adjective

  1. 1

    Having a lively or volatile character; animated, changeable, quick-witted.

    his mercurial temperament

  2. 2

    Pertaining to the astrological influence of the planet Mercury; having the characteristics of a person under such influence (see adjective sense 1).

  3. 3

    Pertaining to the planet Mercury.

  4. 4

    Of or pertaining to the element mercury or quicksilver; containing mercury.

  5. 5

    Caused by the action of mercury or a mercury compound.

  6. 6

    Pertaining to Mercury, the Roman god of, among other things, commerce, financial gain, communication, and thieves and trickery; hence (comparable), money-making; crafty.

    Near-synonym: Hermesian

adjective

as Mercurial
  1. 1

    Alternative letter-case form of mercurial.

Source: English Wiktionary, dump of September 2, 2026 (CC BY-SA 4.0), through kaikki.org (Wiktextract).

How do you pronounce mercurial?

  • UK /məːˈkjʊə.ɹɪ.əl/
  • US /mɝˈkjʊ.ɹi.əl/
  • US /-ˈkjɔ-/

Mercurial has 4 syllables, split mer·cu·ri·al in writing.

Source: English Wiktionary, dump of September 2, 2026 (CC BY-SA 4.0), through kaikki.org (Wiktextract). Recordings: En-uk-mercurial.oga, Wikimedia Commons (author and licence on each file's page).

Forms of mercurial

  • mercurials plural
  • mercuriall
  • more mercurial comparative
  • most mercurial superlative

Source: English Wiktionary, dump of September 2, 2026 (CC BY-SA 4.0), through kaikki.org (Wiktextract).

How common is mercurial?

Mercurial appears about once in every 2 million words in written English, the 36,176th most frequent word form in the list.

Source: written frequency: wordfreq 3.1 (a 2021 snapshot of Wikipedia, subtitles, news, books, web text and social media).

Mercurial in Spanish, French, German and Portuguese

LanguageWords
Frenchlunatique (having a lively or volatile character – see…), mercuriel (containing the element mercury)
Germansprunghaft, launenhaft, lebhaft (having a lively or volatile character – see…), quecksilberhaltig (containing the element mercury)
Spanishlunático, voluble, volátil (having a lively or volatile character – see…), mercurial (pertaining to the Roman god Mercury)
Portuguesemercuriano (pertaining to the Roman god Mercury)

Source: English Wiktionary, dump of September 2, 2026 (CC BY-SA 4.0), through kaikki.org (Wiktextract). Translations are Wiktionary's, by sense; a linked word has its own PlainSpell page.

Where does mercurial come from?

Noun sense 1 (“(obsolete) plant known as mercury”) is from Middle English mercurial (“a plant, probably the goosefoot (Chenopodium); (possibly) dog’s mercury (Mercurialis perennis)”), from Anglo-Norman mercurial, Old French mercurial, or directly from their etymon Latin mercuriālis (“a plant, probably annual mercury (Mercurialis annua)”), short for herba mercuriālis (“(probably) annual mercury”, literally “herb or plant of the god Mercury”).

Source: English Wiktionary, dump of September 2, 2026 (CC BY-SA 4.0), through kaikki.org (Wiktextract).