(a.) Not fixed or firm; liable to change; unstable\; of a changeable mind; not firm in opinion or purpose; inconstant; capricious; as, Fortune's fickle wheel.

adrift afloat agnostic alternating ambiguous ambitendent ambivalent amorphous at loose ends brittle capricious chancy changeable changeful coquettish corruptible deciduous derelict desultory deviable dicey disaffected disloyal dizzy double-minded doubting dubious dying eccentric ephemeral equivocal erratic evanescent faddish fading faithless FALSE fanciful fast and loose fence-sitting fence-straddling fitful fleeting flickering flighty flirtatious flitting fluctuating fly-by-night flying fragile frail freakish frivolous fugacious fugitive giddy hesitant hesitating impermanent impetuous impulsive incalculable inconsistent inconstant indecisive indemonstrable infirm infirm of purpose insubstantial irregular irresolute irresolved irresponsible light lubricious mazy mercurial momentary moody mortal mugwumpian mugwumpish mutable nondurable nonpermanent not true to of bad faith of two minds passing perishable polysemous quicksilver rambling recreant restless roving scatterbrained shapeless shifting shifty short-lived shuffling skeptical skittish spasmodic spineless temperamental temporal temporary ticklish touch-and-go toying transient transitive transitory trothless unaccountable uncertain unconfirmable uncontrolled unconvinced undecided undependable undetermined undisciplined undivinable undurable unenduring unfaithful unfixed unforeseeable unloyal unpersuaded unpredictable unprovable unreliable unresolved unrestrained unsettled unstable unstable as water unstaid unsteadfast unsteady unsure untrue untrustworthy unverifiable vacillating vagrant variable versatile vicissitudinary vicissitudinous volatile wandering wanton wavering wavery wavy wayward whimsical wishy-washy