(a.) Neglect; negligent; heedless; regardless.

airy apathetic arrogant ataractic audacious behindhand blase bold brash brassy brazen bumptious careless casual challenging cheeky cocky contemptuous cursory daring defiant defying degage derisive devil-may-care disdainful disinterested dispassionate disregardant distracted distrait easygoing flippant forgetful free and easy greatly daring heedless impertinent impudent inadvertent inattentive inconsiderate inconstant incurious indifferent inexcitable inobservant insolent insouciant lackadaisical lazy listless mindless negligent nonadherent nonchalant noncompliant nonconforming nonobservant oblivious offhand perfunctory pert pococurante reckless regardless regardless of consequences remiss respectless saucy slack tactless thoughtless turned-off unaccommodating unanxious uncomplaisant uncompliant unconcerned unconforming uncooperative undiplomatic undiscriminating unfaithful unheedful unheeding unhelpful uninterested unloyal unmarking unmindful unnoticing unnoting unobliging unobservant unobserving unprepared unready unremarking unsolicitous untactful unthinking unthoughtful untrue