The Collaborative International Dictionary of English v.0.48:

Efface \Ef*face"\, v. t. [imp. & p. p. Effaced; p. pr. & vb.
   n. Effacing.] [F. effacer; pref. es- (L. ex) + face face;
   prop., to destroy the face or form. See Face, and cf.
   Deface.]
   1. To cause to disappear (as anything impresses or inscribed
      upon a surface) by rubbing out, striking out, etc.; to
      erase; to render illegible or indiscernible; as, to efface
      the letters on a monument, or the inscription on a coin.
      [1913 Webster]

   2. To destroy, as a mental impression; to wear away.
      [1913 Webster]

            Efface from his mind the theories and notions
            vulgarly received.                    --Bacon.

   Syn: To blot out; expunge; erase; obliterate; cancel;
        destroy. -- Efface, Deface. To deface is to injure
        or impair a figure; to efface is to rub out or destroy,
        so as to render invisible.
        [1913 Webster]

WordNet (r) 3.0 (2006):

efface
    v 1: remove completely from recognition or memory; "efface the
         memory of the time in the camps" [syn: obliterate,
         efface]
    2: make inconspicuous; "efface oneself"
    3: remove by or as if by rubbing or erasing; "Please erase the
       formula on the blackboard--it is wrong!" [syn: erase, rub
       out, score out, efface, wipe off]

Moby Thesaurus II by Grady Ward, 1.0:

24 Moby Thesaurus words for "efface":
   annul, black out, blot, blot out, cancel, cross out, dele, delete,
   eliminate, eradicate, erase, exclude, expunge, extirpate,
   obliterate, raze, rub out, rule out, scratch, scratch out, sponge,
   sponge out, strike out, wipe out