The Collaborative International Dictionary of English v.0.48:

Oblivious \Ob*liv"i*ous\, a. [L. obliviosus: cf. F. oblivieux.]
   [1913 Webster]
   1. Promoting oblivion; causing forgetfulness. "The oblivious
      pool." --Milton.
      [1913 Webster]

            She lay in deep, oblivious slumber.   --Longfellow.
      [1913 Webster]

   2. Evincing oblivion; forgetful.
      [1913 Webster]

            Through are both weak in body and oblivious.
                                                  --Latimer.
      [1913 Webster] -- Obliv"i*ous*ly, adv. --
      Ob*liv"i*ous*ness, n. --Foxe.
      [1913 Webster]

The Collaborative International Dictionary of English v.0.48:

obliviousness \ob*liv"i*ous*ness\ n.
   total forgetfulness.

   Syn: oblivion.
        [WordNet 1.5]

WordNet (r) 3.0 (2006):

obliviousness
    n 1: total forgetfulness; "he sought the great oblivion of
         sleep" [syn: obliviousness, oblivion]