The Collaborative International Dictionary of English v.0.48:

Derogate \Der"o*gate\, v. i.
   1. To take away; to detract; to withdraw; -- usually with
      from.
      [1913 Webster]

            If we did derogate from them whom their industry
            hath made great.                      --Hooker.
      [1913 Webster]

            It derogates little from his fortitude, while it
            adds infinitely to the honor of his humanity.
                                                  --Burke.
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   2. To act beneath one-s rank, place, birth, or character; to
      degenerate. [R.]
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            You are a fool granted; therefore your issues, being
            foolish, do not derogate.             --Shak.
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            Would Charles X. derogate from his ancestors? Would
            he be the degenerate scion of that royal line?
                                                  --Hazlitt.
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The Collaborative International Dictionary of English v.0.48:

Derogate \Der"o*gate\, v. t. [imp. & p. p. Derogated; p. pr. &
   vb. n. Derogating.] [L. derogatus, p. p. of derogare to
   derogate; de- + rogare to ask, to ask the people about a law.
   See Rogation.]
   1. To annul in part; to repeal partly; to restrict; to limit
      the action of; -- said of a law.
      [1913 Webster]

            By several contrary customs, . . . many of the civil
            and canon laws are controlled and derogated. --Sir
                                                  M. Hale.
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   2. To lessen; to detract from; to disparage; to depreciate;
      -- said of a person or thing. [R.]
      [1913 Webster]

            Anything . . . that should derogate, minish, or hurt
            his glory and his name.               --Sir T. More.
      [1913 Webster]

The Collaborative International Dictionary of English v.0.48:

Derogate \Der"o*gate\, n. [L. derogatus, p. p.]
   Diminished in value; dishonored; degraded. [R.] --Shak.
   [1913 Webster]

WordNet (r) 3.0 (2006):

derogate
    v 1: cause to seem less serious; play down; "Don't belittle his
         influence" [syn: minimize, belittle, denigrate,
         derogate]