Source : Webster's Revised Unabridged Dictionary (1913)

Oblivious \Ob*liv"i*ous\, a. [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.

Source : WordNet®

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