Source : Webster's Revised Unabridged Dictionary (1913)

Derogation \Der`o*ga"tion\, n. [L. derogatio: cf. F.
   d['e]rogation.]
   1. The act of derogating, partly repealing, or lessening in
      value; disparagement; detraction; depreciation; --
      followed by of, from, or to.

            I hope it is no derogation to the Christian
            religion.                             --Locke.

            He counted it no derogation of his manhood to be
            seen to weep.                         --F. W.
                                                  Robertson.

   2. (Stock Exch.) An alteration of, or subtraction from, a
      contract for a sale of stocks.

Source : WordNet®

derogation
     n 1: a communication that belittles somebody or something [syn: {disparagement},
           {depreciation}]
     2: (law) the partial taking away of the effectiveness of a law;
        a partial repeal or abolition of a law; "any derogation of
        the common law is to be strictly construed"