1. (a.) Inattentive to duty; careless; neglectful; indifferent\.

2. (a.) Rashly negligent; utterly careless or heedless.

accident-prone adventuresome agile airy apathetic ataractic audacious blase brash breakneck carefree careless casual cursory dangerous daredevil daring dashing degage desperate devil-may-care disinterested dispassionate disregardant disregardful double-quick eagle-winged easygoing expeditious express fast feckless fleet flippant flying foolhardy foolish forgetful free and easy furious galloping hair-trigger harum-scarum hasty headlong heedless hopeless hotheaded hurried hustling ill-advised ill-considered ill-contrived ill-devised ill-gauged ill-judged impatient impetuous impolitic imprudent impulsive inadvisable inattentive incautious inconsiderate incurious indifferent indiscreet inexcitable inexpedient injudicious insensate insouciant irrational irresponsible lackadaisical lazy light of heel light-footed listless lively mad madcap mercurial mindless misadvised misguided myopic negligent nimble nimble-footed nonchalant oblivious offhand overeager overenthusiastic overhasty overzealous perfunctory pococurante precipitant precipitate precipitous prompt quick quick as lightning quick as thought rapid rash reasonless regardless respectless running senseless shortsighted slap-bang slapdash snappy spanking speedy sudden swift tactless temerarious thoughtless turned-off unadvised unanxious unconcerned unconsidered undiplomatic undiscerning undiscriminating unforeseeing unheedful unheeding uninterested unmindful unprepared unready unreasonable unreflecting unreflective unseeing unsensible unsolicitous unsound untactful unthinking unthoughtful unwise venturesome venturous wanton wild winged witless