1. (a.) Apt to forget; easily losing remembrance; as, a forgetful man should use helps to strengthen his memory.

2. (a.) Heedless; careless; neglectful; inattentive.

3. (a.) Causing to forget; inducing oblivion; oblivious.

Lethean absent absent-minded absentminded abstracted airy amnesiac amnestic bemused blocked careless casual converted cursory degage disregardant disregardful distracted dreaming dreamy easygoing flippant forgetting free and easy heedless in the clouds inattentive inclined to forget inconsiderate indifferent insouciant lax lazy mindless neglectful negligent oblivious offhand out of it perfunctory preoccupied reckless regardless remiss remote repressed respectless slack suppressed tactless thoughtless unaccommodating uncomplaisant uncooperative undiplomatic unheedful unheeding unhelpful unmindful unobliging unprepared unready unsolicitous untactful unthinking unthoughtful unwitting