Same word as oblivious:

absent, absentminded, absorbed, abstracted, amnesic, blind, blundering, careless, deaf, disregardful, distracted, dreamy, forgetful, forgetting, gone, heedless, inattentive, incognizant, inconversant, insensible, neglectful, negligent, not all there, out to lunch, overlooking, preoccupied, regardless, spacey, strung out, unacquainted, unconcerned, unconscious, undiscerning, unfamiliar, uninformed, uninstructed, unknowing, unmindful, unnoticing, unobservant, unrecognizing, unwitting, zonked