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.

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