Synonyms and related words :
absent, absentminded, abstracted, aloof, apathetic, ataractic, blase, bored, careless, casual, detached, devil-may-care, disinterested, dispassionate, disregardant, disregardful, distant, distracted, distrait, distraught, easygoing, heedless, impassive, inadvertent, inattentive, indifferent, inexcitable, inobservant, insouciant, lackadaisical, listless, mindless, negligent, nonchalant, perfunctory, phlegmatic, pococurante, preoccupied, reckless, regardless, remote, stolid, thoughtless, turned-off, unanxious, unconcerned, undiscriminating, unheedful, unheeding, uninquiring, uninterested, uninvolved, unmarking, unmindful, unnoticing, unnoting, unobservant, unobserving, unremarking, unsolicitous, withdrawn