Lethean, a stranger to, absentminded, airy, aloof, amnestic, apathetic, asleep, ataractic, blase, blind to, blocked, bored, careless, casual, caught napping, converted, cursory, dead to, deaf to, degage, detached, devil-may-care, disinterested, dispassionate, disregardant, disregardful, distant, distracted, distrait, easygoing, flippant, forgetful, forgetting, free and easy, heedless, impassive, impercipient, in ignorance of, inadvertent, inattentive, inclined to forget, incognizant, inconsiderate, incurious, indifferent, inexcitable, inobservant, insensible, insensible to, insouciant, lackadaisical, lazy, listless, mindless, napping, negligent, nonchalant, nonconceiving, not with it, oblivious, offhand, out of it, perfunctory, phlegmatic, pococurante, reckless, regardless, repressed, respectless, stolid, suppressed, tactless, thankless, thoughtless, turned-off, unaccommodating, unanxious, unappreciative, unaware, unaware of, uncomplaisant, unconcerned, unconscious, unconscious of, uncooperative, undiplomatic, undiscriminating, ungrateful, unhearing, unheedful, unheeding, unhelpful, uninquiring, uninsightful, uninterested, uninvolved, unknowing, unmarking, unmindful of, unnoticing, unnoting, unobliging, unobservant, unobserving, unperceiving, unprehensive, unprepared, unready, unrealizing, unremarking, unseeing, unsolicitous, unsuspecting, untactful, unthankful, unthinking, unthoughtful, unwitting, withdrawn, witless