The Collaborative International Dictionary of English v.0.48:

Disorder \Dis*or"der\, n. [Pref. dis- + order: cf. F.
   d['e]sordre.]
   1. Want of order or regular disposition; lack of arrangement;
      confusion; disarray; as, the troops were thrown into
      disorder; the papers are in disorder.
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   2. Neglect of order or system; irregularity.
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            From vulgar bounds with brave disorder part,
            And snatch a grace beyond the reach of art. --Pope.
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   3. Breach of public order; disturbance of the peace of
      society; tumult. --Shak.
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   4. Disturbance of the functions of the animal economy or of
      the soul; sickness; derangement. "Disorder in the body."
      --Locke.

   Syn: Irregularity; disarrangement; confusion; tumult; bustle;
        disturbance; disease; illness; indisposition; sickness;
        ailment; malady; distemper. See Disease.
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The Collaborative International Dictionary of English v.0.48:

Disorder \Dis*or"der\, v. t. [imp. & p. p. Disordered; p. pr.
   & vb. n. Disordering.]
   1. To disturb the order of; to derange or disarrange; to
      throw into confusion; to confuse.
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            Disordering the whole frame or jurisprudence.
                                                  --Burke.
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            The burden . . . disordered the aids and auxiliary
            rafters into a common ruin.           --Jer. Taylor.
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   2. To disturb or interrupt the regular and natural functions
      of (either body or mind); to produce sickness or
      indisposition in; to discompose; to derange; as, to
      disorder the head or stomach.
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            A man whose judgment was so much disordered by party
            spirit.                               --Macaulay.
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   3. To depose from holy orders. [Obs.] --Dryden.

   Syn: To disarrange; derange; confuse; discompose.
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WordNet (r) 3.0 (2006):

disorder
    n 1: a physical condition in which there is a disturbance of
         normal functioning; "the doctor prescribed some medicine
         for the disorder"; "everyone gets stomach upsets from time
         to time" [syn: disorder, upset]
    2: a condition in which things are not in their expected places;
       "the files are in complete disorder" [syn: disorderliness,
       disorder] [ant: order, orderliness]
    3: a disturbance of the peace or of public order [ant: order]
    v 1: disturb in mind or make uneasy or cause to be worried or
         alarmed; "She was rather perturbed by the news that her
         father was seriously ill" [syn: perturb, unhinge,
         disquiet, trouble, cark, distract, disorder]
    2: bring disorder to [syn: disorder, disarray] [ant:
       order]