Synonyms and related words :
airy, careless, casual, cursory, degage, disregardant, disregardful, distracted, distrait, easygoing, flippant, forgetful, free and easy, heedless, inadvertent, inattentive, inconsiderate, incurious, indifferent, inobservant, insouciant, lazy, mindless, negligent, oblivious, offhand, perfunctory, reckless, regardless, respectless, tactless, thoughtless, unaccommodating, uncomplaisant, uncooperative, undiplomatic, unheeding, unhelpful, unmarking, unmindful, unnoticing, unnoting, unobliging, unobservant, unobserving, unprepared, unready, unremarking, unsolicitous, untactful, unthinking, unthoughtful