The Collaborative International Dictionary of English v.0.48:

Execration \Ex`e*cra"tion\, n. [L. execratio, exsecratio: cf. F.
   ex['e]cration.]
   1. The act of cursing; a curse dictated by violent feelings
      of hatred; imprecation; utter detestation expressed.
      [1913 Webster]

            Cease, gentle, queen, these execrations. --Shak.
      [1913 Webster]

   2. That which is execrated; a detested thing.
      [1913 Webster]

            Ye shall be an execration and . . . a curse. --Jer.
                                                  xlii. 18.

   Syn: See Malediction.
        [1913 Webster]

WordNet (r) 3.0 (2006):

execration
    n 1: hate coupled with disgust [syn: abhorrence,
         abomination, detestation, execration, loathing,
         odium]
    2: an appeal to some supernatural power to inflict evil on
       someone or some group [syn: execration, condemnation,
       curse]
    3: the object of cursing or detestation; that which is execrated

Moby Thesaurus II by Grady Ward, 1.0:

75 Moby Thesaurus words for "execration":
   Anglophobia, Russophobia, abhorrence, abomination, abuse, anathema,
   anti-Semitism, antipathy, assailing, assault, attack, aversion,
   ban, berating, bigotry, bitter words, blackening, blasphemy,
   commination, contumely, curse, cursing, cussing, damnation,
   denunciation, despitefulness, detestation, diatribe, dislike,
   evil eye, excommunication, fulmination, hard words, hate, hatred,
   hex, imprecation, invective, jawing, jeremiad, loathing,
   malevolence, malice, malignity, malison, malocchio, misandry,
   misanthropy, misogyny, odium, onslaught, peeve, pet peeve,
   philippic, phobia, profanity, proscription, race hatred, racism,
   rating, repugnance, revilement, screed, spite, spitefulness,
   swearing, thundering, tirade, tongue-lashing, vials of hate,
   vials of wrath, vilification, vituperation, whammy, xenophobia