(a.) Apt to change the mind suddenly; whimsical; capricious.

abnormal adrift afloat alternating amorphous anomalous arbitrary baroque bizarre capricious changeable changeful crank crankish cranky crotchety deformed desultory deviable deviant deviative different divergent dizzy dotty eccentric erratic exceptional fanciful fantasied fantastic fast and loose fey fickle fitful flaky flickering flighty flitting fluctuating freak funny giddy grotesque harebrained humorsome idiocratic idiosyncratic impetuous impulsive inconsistent inconstant indecisive infirm irregular irresolute irresponsible kinky kooky maggoty malformed mazy mercurial misbegotten misshapen monstrous moody motiveless notional nutty odd oddball peculiar petulant queer quirky rambling restless rococo roving scatterbrained screwball screwy shapeless shifting shifty shuffling singular spasmodic spineless strange temperamental teratogenic teratoid twisted unaccountable uncertain uncontrolled unconventional undependable undisciplined unfixed unnatural unpredictable unreasonable unreliable unrestrained unsettled unstable unstable as water unstaid unsteadfast unsteady vacillating vagarious vagrant variable vicissitudinary vicissitudinous volatile wacky wandering wanton wavering wavery wavy wayward whimsical wishy-washy