The Collaborative International Dictionary of English v.0.48:

Dumb \Dumb\, a. [AS. dumb; akin to D. dom stupid, dumb, Sw.
   dumb, Goth. dumbs; cf. Gr. ? blind. See Deaf, and cf.
   Dummy.]
   1. Destitute of the power of speech; unable; to utter
      articulate sounds; as, the dumb brutes.
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            To unloose the very tongues even of dumb creatures.
                                                  --Hooker.
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   2. Not willing to speak; mute; silent; not speaking; not
      accompanied by words; as, dumb show.
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            This spirit, dumb to us, will speak to him. --Shak.
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            To pierce into the dumb past.         -- J. C.
                                                  Shairp.
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   3. Lacking brightness or clearness, as a color. [R.]
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            Her stern was painted of a dumb white or dun color.
                                                  --De Foe.
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   Deaf and dumb. See Deaf-mute.

   Dumb ague, or Dumb chill, a form of intermittent fever
      which has no well-defined "chill." [U.S.]

   Dumb animal, any animal except man; -- usually restricted
      to a domestic quadruped; -- so called in contradistinction
      to man, who is a "speaking animal."

   Dumb cake, a cake made in silence by girls on St. Mark's
      eve, with certain mystic ceremonies, to discover their
      future husbands. --Halliwell.

   Dumb cane (Bot.), a west Indian plant of the Arum family
      (Dieffenbachia seguina), which, when chewed, causes the
      tongue to swell, and destroys temporarily the power of
      speech.

   Dumb crambo. See under crambo.

   Dumb show.
      (a) Formerly, a part of a dramatic representation, shown
          in pantomime. "Inexplicable dumb shows and noise."
          --Shak.
      (b) Signs and gestures without words; as, to tell a story
          in dumb show.

   To strike dumb, to confound; to astonish; to render silent
      by astonishment; or, it may be, to deprive of the power of
      speech.

   Syn: Silent; speechless; noiseless. See Mute.
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