The Collaborative International Dictionary of English v.0.48:

Deprave \De*prave"\ (d[-e]*pr[=a]v"), v. t. [imp. & p. p.
   Depraved (d[-e]*pr[=a]vd"); p. pr. & vb. n. Depraving.]
   [L. depravare, depravatum; de- + pravus crooked, distorted,
   perverse, wicked.]
   1. To speak ill of; to depreciate; to malign; to revile.
      [Obs.]
      [1913 Webster]

            And thou knowest, conscience, I came not to chide
            Nor deprave thy person with a proud heart. --Piers
                                                  Plowman.
      [1913 Webster]

   2. To make bad or worse; to vitiate; to corrupt.
      [1913 Webster]

            Whose pride depraves each other better part.
                                                  --Spenser.

   Syn: To corrupt; vitiate; contaminate; pollute.
        [1913 Webster]