mercurial
/məːˈkjʊə.ɹɪ.əl/
mercurial means having a lively or volatile character; animated, changeable, quick-witted.
mercurial is pronounced /məːˈkjʊə.ɹɪ.əl/.
Why “mercurial” is a great word
Characterized by a rapid and unpredictable changeability of mood or mind, lively, volatile, and quick-witted. From the Latin Mercurialis ("pertaining to the Roman god Mercury"), from Mercurius ("Mercury"), the swift messenger god, with the adjective suffix -alis. Unlike "capricious," which suggests a change born of fleeting whim, or "stable," which denotes an anchored resistance, "mercurial" describes an elemental volatility, an intelligence in constant, liquid motion. It is the quicksilver bead that splits and re-coalesces, the conversation that leaps from gravity to jest in a breath, the sudden shadow that passes over a sunlit face—an untetherable spirit forever in flight from its own previous state.
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 plan
adj
- Having a lively or volatile character; animated, changeable, quick-witted.“his mercurial temperament”
- Pertaining to the astrological influence of the planet Mercury; having the characteristics of a person under such influence (see adjective sense 1).“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.”
- Pertaining to the planet Mercury.
- Of or pertaining to the element mercury or quicksilver; containing mercury.“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, [...]”
- Caused by the action of mercury or a mercury compound.“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.”
- 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”
noun
- Any of the plants known as mercury, especially the annual mercury or French mercury (Mercurialis annua).
- A person born under the influence of the planet Mercury; hence, a person having an eloquent, quickwitted, furtive, or volatile character.“As for [Lambert] Simnell, there was not much in him, more then that hee was a handſome Boy, and did not ſhame his Robes. But this Youth (of whom wee are now to ſpeake) was ſuch a Mercuriall, as the like hath ſeldome beene knowne; and could make his owne part, if at any time hee chanced to bee out.”
- A chemical compound containing mercury.
- A preparation of mercury, especially as a treatment for syphilis.“She had paſſed through the milder Remedies frequently without ſucceſs: upon which account I deſigned Mercurialls; and beginning with Venæſection, afterwards purged her with decoct. epithymi, as it is preſcribed in the method of Cure. [...] After I had thus evacuated the Plethora, and diſpoſed her body for Mercurialls more operative, I gave her each morning and evening a few grains of Mercur. diaph”
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