Source : Webster's Revised Unabridged Dictionary (1913)

Deprecation \Dep`re*ca"tion\ (d[e^]p`r[-e]*k[=a]"sh[u^]n), n.
   [L. deprecatio; cf. F. d['e]pr['e]cation.]
   1. The act of deprecating; a praying against evil; prayer
      that an evil may be removed or prevented; strong
      expression of disapprobation.

            Humble deprecation.                   --Milton.

   2. Entreaty for pardon; petitioning.

   3. An imprecation or curse. [Obs.] --Gilpin.

Source : WordNet®

deprecation
     n 1: a prayer to avert or remove some evil or disaster
     2: the act of expressing disapproval (especially of yourself)
        [syn: {denigration}]