1. (a.) Promoting oblivion; causing forgetfulness.

2. (a.) Evincing oblivion; forgetful.

Lethean absent absent-minded absentminded absorbed abstracted airy amnestic asleep bemused blank blankminded blind blind to blocked calm careless castle-building casual cataleptic catatonic cold comatose converted cursory daydreaming daydreamy dead dead asleep dead to deaf deaf to deep asleep degage detached disregardant disregardful distant doped dormant dreaming dreamy drowsing drugged easygoing ecstatic elsewhere empty empty-headed engrossed faraway fast asleep fatuous flaked-out flippant forgetful forgetting free and easy half-awake half-conscious heedless in a reverie in the clouds inane inclined to forget incogitant incognizant inconsiderate indifferent insensible insensitive insouciant lazy lost lost in thought lost to meditative mooning moonraking museful musing napping narcotized nirvanic nodding offhand out out cold out of it passive pensive perfunctory pipe-dreaming preoccupied quietistic rapt reckless regardless relaxed removed repressed respectless semiconscious senseless sleeping slumbering somewhere else sound asleep spaced out stargazing stoned strung out suppressed tactless taken up thoughtfree thoughtless tranquil transported unacquainted unaware unconcerned unconscious undiplomatic unfamiliar unfeeling unheedful unheeding unideaed uninformed uninstructed unintellectual unknowing unmindful unoccupied unprepared unready unreasoning unsolicitous untactful unthinking unwitting vacant vacuous woolgathering wrapped in thought zonked zonked out