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