1. (a.) Swift; active; sprightly; fickle; volatile; changeable; as, a mercurial youth; a mercurial temperament; having the qualities fabled to belong to the god Mercury.
2. (a.) Having the form or image of Mercury; -- applied to ancient guideposts.
3. (a.) of or pertaining to Mercury as the god of trade; hence, money-making; crafty.
4. (a.) of or pertaining to, or containing, mercury; as, mercurial preparations, barometer. See Mercury, 2.
5. (a.) Caused by the use of mercury; as, mercurial sore mouth.
6. (n.) A person having mercurial qualities.
7. (n.) A preparation containing mercury.
Thesaurus Entries
active, activist, activistic, adrift, adroit, afloat, agile, alive, alternating, ambitendent, ambivalent, amorphous, animated, at loose ends, aureate, bouncing, bouncy, brass, brassy, brazen, breakneck, breezy, brisk, bronze, bronzy, bubbly, buoyant, capricious, changeable, changeful, changing, chipper, choppy, clever, copper, coppery, coquettish, cunning, cupreous, cuprous, dashing, desultory, deviable, deviating, deviative, deviatory, different, disorderly, divaricate, divergent, diversified, diversiform, dizzy, double-minded, double-quick, dubious, eagle-winged, ebullient, eccentric, effervescent, elastic, energetic, erose, erratic, expansive, expeditious, express, faddish, fast, fast and loose, fence-sitting, fence-straddling, ferrous, ferruginous, fickle, fitful, fleet, flickering, flighty, flirtatious, flitting, fluctuating, flying, freakish, frisky, full of go, full of life, full of pep, galloping, giddy, gilt, gold, gold-filled, gold-plated, golden, hair-trigger, hasty, headlong, hustling, impetuous, impulsive, inconsistent, inconstant, indecisive, infirm, infirm of purpose, ingenious, iron, ironlike, irregular, irresolute, irresolved, irresponsible, jagged, jerky, lead, leaden, light, light of heel, light-footed, live, lively, lubricious, mazy, mercurous, militant, mobile, moody, motley, movable, mugwumpian, mugwumpish, mutable, nickel, nickelic, nickeline, nimble, nimble-footed, nonconformist, nonstandard, nonuniform, of two minds, peppy, perky, pert, pewter, pewtery, pluralistic, precipitate, prompt, quick, quick as lightning, quick as thought, quicksilver, ragged, rambling, rapid, reckless, resilient, restless, rough, roving, running, scatterbrained, shapeless, shifting, shifty, shuffling, silver, silver-plated, silvery, skittish, smacking, snappy, spanking, spasmodic, speedy, spineless, spirited, sporadic, sprightly, spry, steel, steely, swift, temperamental, ticklish, tin, tinny, toying, unaccountable, uncertain, uncontrolled, undecided, undependable, undetermined, undisciplined, unequable, unequal, uneven, unfixed, unorthodox, unpredictable, unreliable, unresolved, unrestrained, unsettled, unstable, unstable as water, unstaid, unsteadfast, unsteady, unsystematic, ununiform, vacillating, vagrant, variable, variegated, variform, various, varying, versatile, vicissitudinary, vicissitudinous, vivacious, volatile, wandering, wanton, wavering, wavery, wavy, wayward, whimsical, winged, wishy-washy, zingy
