Word: mercurial Part of Speech: adj Etymology: 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”). Mercuriālis (“pertaining to the Roman god Mercury”, adjective) is derived from Mercurius (“the Roman god Mercury”) + -ālis (suffix forming adjectives of relationship from nouns). Later adjective and noun uses may have been directly derived from Latin mercuriālis (adjective), whence Middle English mercurial (“under the astrological influence of the planet Mercury”). Pronunciation: /məːˈkjʊə.ɹɪ.əl/, /mɝˈkjʊ.ɹi.əl/, /-ˈkjɔ-/ 1. Having a lively or volatile character; animated, changeable, quick-witted. Labels: comparable Example: his mercurial temperament Example: [Y]our Mercuriall wit hath mangonized a Gigantean fury with an humble hue. 2. Pertaining to the astrological influence of the planet Mercury; having the characteristics of a person under such influence (see adjective sense 1). Labels: not-comparable Example: The Sun to the Terms of Mercury. It inclineth the native to be Mercurial, given to ſtudy Arts and Sciences, and to delight in reading, and to follow his Calling with chearfulneſs. Example: 6thly, The ☽ separates from a △ of ♂︎, and applies to ☍ of ☿, lord of the 3d; which intimated that some neighbour of the querent, either with a letter, words, or cross information, would wholly destroy the querent's hopes; and that mercurial men, viz. scholars or divines, would be his enemies: [...] 3. Pertaining to the planet Mercury. Labels: not-comparable 4. Of or pertaining to the element mercury or quicksilver; containing mercury. Labels: not-comparable Example: Beware alſo of Mercuriall lotions, I meane any which haue Mercurie Sublimate Precipitat or otherwiſe prepared in them, for though they haue good qualities, yet they are vpon my knowledge and experience dangerous, [...] Example: [...] Dr. Francis Fuller, [...] upon wearing a Quick-ſilver Girdle, for the Cure of the Itch, (and that after an inconſiderate and raſh manner) was brought under a violent Spaſmodick Diſtemper, which was ſupposed by himſelf and others to be owing to ſome Mercurial Particles lodg'd in ſome excretory Ducts of the Brain. 5. Caused by the action of mercury or a mercury compound. Labels: not-comparable Example: I ſaw in the Year 1709. a notable inſtance, where a Phyſician order'd the Patient to be Bled five times in a Mercurial Salivation in a Caſe not Venereal; when he did ſpit at the rate of ℔ iv. per diem, and it was at the height, and yet notwithſtanding it did continue for all this, and the Patient eſcap'd with his Life. Example: The last exciting cause of the mercurial ulcer, which I shall now mention, is the use of the knife or of the caustic, during a mercurial course, to wounds made or enlarged at this time; for the great additional irritation, which the operation must produce, disposes such wounds to take on easily the mercurial disease. 6. Pertaining to Mercury, the Roman god of, among other things, commerce, financial gain, communication, and thieves and trickery; hence (comparable), money-making; crafty. Labels: Roman, not-comparable Example: Near-synonym: Hermesian Example: 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?