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®

oblivious
     adj 1: (followed by `to' or `of') lacking conscious awareness of;
            "oblivious of the mounting pressures for political
            reform"; "oblivious to the risks she ran"; "not
            unmindful of the heavy responsibility" [syn: {oblivious(p)},
             {unmindful(p)}]
     2: failing to keep in mind; "forgetful of her
        responsibilities"; "oblivious old age" [syn: {forgetful}]