The Collaborative International Dictionary of English v.0.48:

Derision \De*ri"sion\, n. [L. derisio: cf. F. d['e]rision. See
   Deride.]
   1. The act of deriding, or the state of being derided;
      mockery; scornful or contemptuous treatment which holds
      one up to ridicule.
      [1913 Webster]

            He that sitteth in the heavens shall laugh; the Lord
            shall have them in derision.          --Ps. ii. 4.
      [1913 Webster]

            Satan beheld their plight,
            And to his mates thus in derision called. --Milton.
      [1913 Webster]

   2. An object of derision or scorn; a laughing-stock.
      [1913 Webster]

            I was a derision to all my people.    --Lam. iii.
                                                  14.

   Syn: Scorn; mockery; contempt; insult; ridicule.
        [1913 Webster]

WordNet (r) 3.0 (2006):

derision
    n 1: contemptuous laughter
    2: the act of deriding or treating with contempt [syn:
       derision, ridicule]

Moby Thesaurus II by Grady Ward, 1.0:

22 Moby Thesaurus words for "derision":
   burlesque, butt, caricature, contempt, contumely, disrespect, jest,
   joke, lampoon, laughter, mock, mockery, pasquinade, pilgarlic,
   raillery, ridicule, sarcasm, satire, scoffing, scorn, sport,
   travesty