mercurial

Etymology

It is inherited from Middle English mercurial,^[2][3] borrowed from Old French mercurial, the Anglo-Norman and Old French form, and directly borrowed from Latin mercuriālis (“of the god or planet Mercury”).^[3][4][5] The Latin adjective is formed from Mercurius (“Mercury”), the Roman god of commerce and messenger of the gods, and also the planet, with the suffix -ālis.^[6][7][3] The planet's Latin name, stella Mercurii (“star of Mercury”), translated a Greek name meaning "star of Hermes".^[6][8] The earliest English use, as a noun naming the plant mercury, follows the Anglo-Norman and Old French noun, recorded from the 13th century,^[3][9] or Latin herba mercuriālis; the OED takes the later adjective and noun as borrowed again from Latin.^[3] Other dictionaries give only the Latin source,^[7][4][10] while the Shorter Oxford also names French mercuriel.^[5]

Earliest recorded meaning

The plant mercury, in a Latin–English word list of before 1300, which glosses Latin Mercurialis;^[3][2] the Anglo-Norman noun had the same sense from 1235–55.^[9] The adjective is first recorded before 1393, in Gower's Confessio Amantis, for a star under the influence of the planet Mercury.^[2][3] Etymonline dates the adjective to the late 14th century.^[7]

Semantic evolution

The adjective began as an astrological word: of the planet Mercury, or under its influence.^[3][2][7] From 1556 a mercurial was a person born under that planet, or having the qualities thought to follow from such a birth,^[3][11] and the adjective was used of such people from 1593.^[3] Senses relating to the god Mercury, as patron of trade and as herald and guide, are recorded from about 1487 (Etymonline: the 1590s).^[3][7] The general sense "lively, quick-witted, volatile" dates from 1647; the OED's 1989 edition explains it as a use of the astrological sense, now commonly taken to allude to the properties of quicksilver,^[12][11] and Etymonline likewise traces it to the qualities of people born under Mercury, partly reinforced by quicksilver.^[7] Johnson (1755) defined the word as formed under the influence of Mercury, "active; sprightly", with a quotation from Shakespeare's Cymbeline,^[13] and Brewer explained it as light-hearted, like those born under the planet.^[14] Today the main sense is unpredictable changeableness of mood.^[6][15] Separately, from 1559 the adjective was used of the metal mercury,^[3][11] while from 1676 a mercurial was a medicine prepared from mercury, especially as a treatment for syphilis.^[3][16]

Timeline

• before 1300 – the plant mercury (obsolete by 1626).^[3][2]
• before 1393 – of or influenced by the planet Mercury.^[3][2]
• c. 1487 – of or resembling the god Mercury.^[3]
• 1556 – noun, a person born under the planet Mercury.^[3][6]
• 1559 – of or containing the metal mercury.^[3]
• 1593 – of a person, born under Mercury and having its qualities.^[3]
• 1647 – lively, quick-witted, volatile.^[11][12] Etymonline dates it to the 1640s.^[7]
• 1676 – noun, a medicine prepared from mercury.^[3][16]

Meanings

Adjective

1. Changing mood or mind quickly and unpredictably; volatile, temperamental: Her mercurial boss praised the report one day and tore it apart the next.^[6][15]
2. Lively, sprightly and quick-witted.^[15][11][12]
3. Of, relating to or containing the metal mercury (quicksilver).^[15][16][3]
4. Of or like the god Mercury, or having the eloquence, ingenuity or thievishness attributed to him.^[16][3][15]
5. Of, relating to or born under the planet Mercury.^[16][3][15]

Noun

1. (medicine) A drug or other preparation containing mercury.^[15][16][3]
2. (astrology) A person born under the planet Mercury, or having the lively qualities ascribed to such a birth.^[3] Merriam-Webster Unabridged marks it obsolete.^[6]
3. (obsolete, 1300–1626) The plant mercury, especially Mercurialis annua.^[3][2]

Word family

• mercurially
• mercurialness
• unmercurial
• mercurialize
• mercurialism
• organomercurial

Related words

• mercuric
• mercury

References

1. ^ a b Wiktionary, the free dictionary, https://en.wiktionary.org
2. ^ a b c d e f g Kurath, Hans; Kuhn, Sherman M.; Lewis, Robert E., eds. (1952–2001), Middle English Dictionary, Ann Arbor: University of Michigan Press; online edition ed. Frances McSparran et al. (2000–2018)
3. ^ a b c d e f g h i j k l m n o p q r s t u v w x y z Oxford English Dictionary Online (accessed March 2026), Oxford: Oxford University Press
4. ^ a b The American Heritage Dictionary of the English Language (online 2024), 5th ed., Boston: Houghton Mifflin Harcourt
5. ^ a b Shorter Oxford English Dictionary on Historical Principles (2002), 5th ed., ed. William R. Trumble and Angus Stevenson, Oxford: Oxford University Press
6. ^ a b c d e f Merriam-Webster Unabridged Dictionary (2024), online ed., Springfield, Mass.: Merriam-Webster
7. ^ a b c d e f g Harper, Douglas. Online Etymology Dictionary, https://www.etymonline.com
8. ^ Merriam-Webster's Book of Word Histories, Springfield, Mass.: Merriam-Webster
9. ^ a b Anglo-Norman Dictionary (AND2), Aberystwyth University, anglo-norman.net (2nd ed., 2005–)
10. ^ Soanes, Catherine; Stevenson, Angus, eds. (2004), Concise Oxford English Dictionary, 11th ed., Oxford: Oxford University Press
11. ^ a b c d e Kay, Christian; Roberts, Jane; Samuels, Michael; Wotherspoon, Irené, eds. (2009), Historical Thesaurus of the Oxford English Dictionary, Oxford: Oxford University Press; online edition (2024)
12. ^ a b c Simpson, J. A.; Weiner, E. S. C., eds. (1989), The Oxford English Dictionary, 2nd ed., Oxford: Clarendon Press
13. ^ Johnson, Samuel (1755), A Dictionary of the English Language, London; 4th ed. 1773; Johnson's Dictionary Online, ed. Beth Rapp Young et al.
14. ^ Brewer, E. Cobham (1898), Dictionary of Phrase and Fable, new ed., London: Cassell
15. ^ a b c d e f g Collins English Dictionary (2023), Glasgow: HarperCollins
16. ^ a b c d e f Merriam-Webster's Collegiate Dictionary (2003), 11th ed., Springfield, Mass.: Merriam-Webster