(a.) Acting of one's self or of itself; acting without depending on other agents.

absolute absolutist absolutistic aristocratic arrogant autarchic authoritarian authoritative autocratic autonomous bossy capricious careless chance chancy cranky crotchety despotic dictatorial discretional discretionary dogmatic domineering doubtful elective erratic fanciful fantasied fantastic feudal flaky freakish free free will gratuitous grinding harebrained heedless high-handed humorsome iffy imperative imperial imperious impetuous inadvertent inconsiderate inconsistent independent indiscreet irrational kinky kooky lordly maggoty magisterial magistral masterful monocratic moody motiveless nonmandatory notional offered oppressive optional oracular overbearing overruling peremptory petulant precipitate proffered quirky random rash reasonless repressive screwball self-acting self-active self-determined self-determining severe spontaneous strict subjective summary suppressive temperamental thoughtless tyrannical tyrannous unasked unbesought unbidden uncalculating uncalled-for uncertain uncoerced uncompelled uncompromising unconstrained undisciplined unforced unguarded uninfluenced uninvited unpredictable unpressured unprompted unreasonable unreasoning unreflecting unrequested unrequired unrestrained unruly unsolicited unsought unthinking unthoughtful vagarious vagrant varying voluntary volunteer wanton wayward whimsical wild willful zany