Oblivious, a.
Etymology: [L.obliviosus: cf.F. oblivieux.]
1. Promoting oblivion; causing forgetfulness. "The oblivious pool." Milton. She lay in deep, oblivious slumber. Longfellow.
2. Evincing oblivion; forgetful. Through are both weak in body and oblivious. Latimer. -- Obliv"i*ous*ly, adv. -- Ob*liv"i*ous*ness, n. Foxe.
Shades of meaning
Fernald has no entry of its own for oblivious; he lists it under abstracted.
Where he writes about it:
The absent-minded man is oblivious of ordinary matters, because his thoughts are elsewhere. — from abstracted