The Collaborative International Dictionary of English v.0.48:

Depravity \De*prav"i*ty\, n. [From Deprave: cf. L. pravitas
   crookedness, perverseness.]
   The state of being depraved or corrupted; a vitiated state of
   moral character; general badness of character; wickedness of
   mind or heart; absence of religious feeling and principle.
   [1913 Webster]

   Total depravity. See Original sin, and Calvinism.

   Syn: Corruption; vitiation; wickedness; vice; contamination;
        degeneracy.

   Usage: Depravity, Depravation, Corruption. Depravilty
          is a vitiated state of mind or feeling; as, the
          depravity of the human heart; depravity of public
          morals. Depravation points to the act or process of
          making depraved, and hence to the end thus reached;
          as, a gradual depravation of principle; a depravation
          of manners, of the heart, etc. Corruption is the only
          one of these words which applies to physical
          substances, and in reference to these denotes the
          process by which their component parts are dissolved.
          Hence, when figuratively used, it denotes an utter
          vitiation of principle or feeling. Depravity applies
          only to the mind and heart: we can speak of a depraved
          taste, or a corrupt taste; in the first we introduce
          the notion that there has been the influence of bad
          training to pervert; in the second, that there is a
          want of true principle to pervert; in the second, that
          there is a want of true principles to decide. The
          other two words have a wider use: we can speak of the
          depravation or the corruption of taste and public
          sentiment. Depravity is more or less open; corruption
          is more or less disguised in its operations. What is
          depraved requires to be reformed; what is corrupt
          requires to be purified.
          [1913 Webster]

WordNet (r) 3.0 (2006):

depravity
    n 1: moral perversion; impairment of virtue and moral
         principles; "the luxury and corruption among the upper
         classes"; "moral degeneracy followed intellectual
         degeneration"; "its brothels, its opium parlors, its
         depravity"; "Rome had fallen into moral putrefaction" [syn:
         corruption, degeneracy, depravation, depravity,
         putrefaction]
    2: a corrupt or depraved or degenerate act or practice; "the
       various turpitudes of modern society" [syn: depravity,
       turpitude]

Moby Thesaurus II by Grady Ward, 1.0:

65 Moby Thesaurus words for "depravity":
   abandon, abandonment, abjection, abjectness, abominableness,
   atrociousness, baseness, beggarliness, contemptibility,
   contemptibleness, corruptedness, corruption, corruptness,
   crumminess, debasement, decadence, decadency, degeneracy,
   degenerateness, degeneration, degradation, demoralization,
   depravation, depravedness, despicableness, dissoluteness, enormity,
   execrableness, foulness, fulsomeness, grossness, heinousness,
   immorality, littleness, lowness, meanness, miserableness,
   monstrousness, moral pollution, moral turpitude, nefariousness,
   obnoxiousness, odiousness, paltriness, pettiness, pokiness,
   poorness, profligacy, rankness, reprobacy, rottenness, scabbiness,
   scrubbiness, scruffiness, scumminess, scurviness, shabbiness,
   shoddiness, smallness, squalor, turpitude, vice, vileness,
   wickedness, wretchedness