WordNet (r) 3.0 (2006):

blot out
    v 1: make undecipherable or imperceptible by obscuring or
         concealing; "a hidden message"; "a veiled threat" [syn:
         obscure, blot out, obliterate, veil, hide]

Moby Thesaurus II by Grady Ward, 1.0:

91 Moby Thesaurus words for "blot out":
   abate, abbreviate, abolish, abridge, annul, becloud, bedarken,
   bedim, begloom, black, black out, blacken, blast, block the light,
   blot, blue-pencil, bowdlerize, brown, bump off, cancel,
   cast a shadow, censor, cloud, cloud over, croak, cross out, cut,
   darken, darken over, dele, delete, dim, dim out, do in, eclipse,
   edit, edit out, efface, encloud, encompass with shadow, eradicate,
   erase, expunge, expurgate, exterminate, extinguish, extirpate, fix,
   get, give the business, gloom, gun down, hit, ice, kill, lay out,
   murk, obfuscate, obliterate, obnubilate, obscure, obumbrate,
   occult, occultate, off, omit, overcast, overcloud, overshadow,
   polish off, raze, rescind, root out, rub out, rule out, scratch,
   scratch out, settle, shade, shadow, somber, sponge, sponge out,
   strike, strike off, strike out, take care of, void, waste,
   wipe out, zap