The Collaborative International Dictionary of English v.0.48:

derogatory \de*rog"a*to*ry\, a.
   Tending to derogate, or lessen in value; expressing a low
   opinion; expressing derogation; detracting; injurious; --
   with from, to, or unto.

   Syn: belittling, depreciative, deprecatory, depreciatory,
        derogatory, detractive, detracting, slighting,
        pejorative, denigratory.
        [1913 Webster]

              Acts of Parliament derogatory from the power of
              subsequent Parliaments bind not.    --Blackstone.
        [1913 Webster]

              His language was severely censured by some of his
              brother peers as derogatory to their other.
                                                  --Macaulay.
        [1913 Webster]

   Derogatory clause in a testament (Law), a sentence of
      secret character inserted by the testator alone, of which
      he reserves the knowledge to himself, with a condition
      that no will he may make thereafter shall be valid, unless
      this clause is inserted word for word; -- a precaution to
      guard against later wills extorted by violence, or
      obtained by suggestion.
      [1913 Webster]

WordNet (r) 3.0 (2006):

derogatory
    adj 1: expressive of low opinion; "derogatory comments";
           "disparaging remarks about the new house" [syn:
           derogative, derogatory, disparaging]

Moby Thesaurus II by Grady Ward, 1.0:

64 Moby Thesaurus words for "derogatory":
   abasing, abusive, back-biting, belittling, bitchy, calumniatory,
   calumnious, catty, censorious, contemptuous, contumelious,
   debasing, defamatory, deflating, degrading, demeaning, deprecatory,
   depreciating, depreciative, depreciatory, derisive, derisory,
   derogative, despiteful, detracting, detractory, diminishing,
   disadvantageous, discreditable, disdainful, dishonorable,
   disparaging, disreputable, humiliating, ignoble, ignominious,
   infamous, inglorious, insulting, libelous, lowering, malevolent,
   malicious, maligning, minimizing, mitigating, notorious, offensive,
   pejorative, ridiculing, scandalous, scurrile, scurrilous, seamy,
   shady, slanderous, slighting, sordid, spiteful, uncomplimentary,
   unpraiseworthy, unrespectable, unsavory, vilifying