The Collaborative International Dictionary of English v.0.48:

Distemper \Dis*tem"per\, n. [See Distemper, v. t., and cf.
   Destemprer.]
   1. An undue or unnatural temper, or disproportionate mixture
      of parts. --Bacon.
      [1913 Webster]

   Note: This meaning and most of the following are to be
         referred to the Galenical doctrine of the four "humors"
         in man. See Humor. According to the old physicians,
         these humors, when unduly tempered, produce a
         disordered state of body and mind.
         [1913 Webster]

   2. Severity of climate; extreme weather, whether hot or cold.
      [Obs.]
      [1913 Webster]

            Those countries . . . under the tropic, were of a
            distemper uninhabitable.              --Sir W.
                                                  Raleigh.
      [1913 Webster]

   3. A morbid state of the animal system; indisposition;
      malady; disorder; -- at present chiefly applied to
      diseases of brutes; as, a distemper in dogs; the horse
      distemper; the horn distemper in cattle.
      [1913 Webster]

            They heighten distempers to diseases. --Suckling.
      [1913 Webster]

   4. Morbid temper of the mind; undue predominance of a passion
      or appetite; mental derangement; bad temper; ill humor.
      [Obs.]
      [1913 Webster]

            Little faults proceeding on distemper. --Shak.
      [1913 Webster]

            Some frenzy distemper had got into his head.
                                                  --Bunyan.
      [1913 Webster]

   5. Political disorder; tumult. --Waller.
      [1913 Webster]

   6. (Paint.)
      (a) A preparation of opaque or body colors, in which the
          pigments are tempered or diluted with weak glue or
          size (cf. Tempera) instead of oil, usually for scene
          painting, or for walls and ceilings of rooms.
      (b) A painting done with this preparation.

   Syn: Disease; disorder; sickness; illness; malady;
        indisposition; ailment. See Disease.
        [1913 Webster]

The Collaborative International Dictionary of English v.0.48:

Distemper \Dis*tem"per\, v. t. [imp. & p. p. Distempered; p.
   pr. & vb. n. Distempering.] [OF. destemprer, destremper, to
   distemper, F. d['e]tremper to soak, soften, slake (lime);
   pref. des- (L. dis-) + OF. temprer, tremper, F. tremper, L.
   temperare to mingle in due proportion. See Temper, and cf.
   Destemprer.]
   1. To temper or mix unduly; to make disproportionate; to
      change the due proportions of. [Obs.]
      [1913 Webster]

            When . . . the humors in his body ben distempered.
                                                  --Chaucer.
      [1913 Webster]

   2. To derange the functions of, whether bodily, mental, or
      spiritual; to disorder; to disease. --Shak.
      [1913 Webster]

            The imagination, when completely distempered, is the
            most incurable of all disordered faculties.
                                                  --Buckminster.
      [1913 Webster]

   3. To deprive of temper or moderation; to disturb; to ruffle;
      to make disaffected, ill-humored, or malignant.
      "Distempered spirits." --Coleridge.
      [1913 Webster]

   4. To intoxicate. [R.]
      [1913 Webster]

            The courtiers reeling,
            And the duke himself, I dare not say distempered,
            But kind, and in his tottering chair carousing.
                                                  --Massinger.
      [1913 Webster]

   5. (Paint.) To mix (colors) in the way of distemper; as, to
      distemper colors with size. [R.]
      [1913 Webster]

WordNet (r) 3.0 (2006):

distemper
    n 1: any of various infectious viral diseases of animals
    2: an angry and disagreeable mood [syn: ill humor, ill
       humour, distemper] [ant: amiability, good humor, good
       humour, good temper]
    3: paint made by mixing the pigments with water and a binder
    4: a painting created with paint that is made by mixing the
       pigments with water and a binder
    5: a method of painting in which the pigments are mixed with
       water and a binder; used for painting posters or murals or
       stage scenery
    v 1: paint with distemper

Moby Thesaurus II by Grady Ward, 1.0:

166 Moby Thesaurus words for "distemper":
   Texas fever, abnormality, acute disease, affection, affliction,
   ailment, allergic disease, allergy, anarchism, anarchy, anthrax,
   aphthous fever, atrophy, bacterial disease, bighead, birth defect,
   black quarter, blackleg, blackwater, blight, blind staggers,
   bloody flux, broken wind, cardiovascular disease, cattle plague,
   charbon, chromogen, chronic disease, circulatory disease, coat,
   coat of paint, coating, color, color filter, color gelatin,
   colorant, coloring, complaint, complication, condition,
   congenital defect, dead-color, defect, deficiency disease,
   deformity, degenerative disease, derange, disability, disarrange,
   disarray, discompose, disease, disjoint, disorder, disturb, drier,
   dye, dyestuff, endemic, endemic disease, endocrine disease,
   epidemic disease, exterior paint, flat coat, flat wash,
   floor enamel, foot-and-mouth disease, functional disease,
   fungus disease, gapes, gastrointestinal disease, genetic disease,
   glanders, ground, handicap, heaves, hereditary disease,
   hog cholera, hoof-and-mouth disease, hydrophobia,
   iatrogenic disease, illness, indisposition, infectious disease,
   infirmity, interior paint, liver rot, loco, loco disease, locoism,
   mad staggers, malady, malaise, malignant catarrh,
   malignant catarrhal fever, malignant pustule, mange, medium,
   megrims, milzbrand, misrule, mix up, morbidity, morbus, muddle,
   muscular disease, neurological disease, nutritional disease,
   occupational disease, opaque color, organic disease, paint,
   pandemic disease, paratuberculosis, pathological condition,
   pathology, pigment, pip, plant disease, prime coat, primer,
   priming, protozoan disease, pseudotuberculosis,
   psychosomatic disease, quarter evil, rabies, respiratory disease,
   rinderpest, riot, rockiness, rot, rummage, scabies,
   secondary disease, seediness, sheep rot, sickishness, sickness,
   signs, splenic fever, staggers, stain, stringhalt, swine dysentery,
   symptomatology, symptomology, symptoms, syndrome, tempera, the pip,
   thinner, tinction, tincture, transparent color, turpentine, turps,
   undercoat, undercoating, urogenital disease, vehicle,
   virus disease, wash, wash coat, wasting disease, worm disease