adjective

given to sudden and unaccountable changes of mood or behaviour.

it’s terrible to feel our livelihood hinges on a capricious boss

fickle,inconstant,changeable,variable,unstable,mercurial,volatile,erratic,vacillating,irregular,inconsistent,fitful,arbitrary,impulsive,temperamental,wild,ungovernable,whimsical,fanciful,flighty,wayward,quirky,faddish,freakish,unpredictable,random,chance,haphazard