Source : Webster's Revised Unabridged Dictionary (1913)

Crazy \Cra"zy\ (kr[=a]"z[y^]), a. [From {Craze}.]
   1. Characterized by weakness or feebleness; decrepit; broken;
      falling to decay; shaky; unsafe.

            Piles of mean andcrazy houses.        --Macaulay.

            One of great riches, but a crazy constitution.
                                                  --Addison.

            They . . . got a crazy boat to carry them to the
            island.                               --Jeffrey.

   2. Broken, weakened, or dissordered in intellect; shattered;
      demented; deranged.

            Over moist and crazy brains.          --Hudibras.

   3. Inordinately desirous; foolishly eager. [Colloq.]

            The girls were crazy to be introduced to him. --R.
                                                  B. Kimball.

   {Crazy bone}, the bony projection at the end of the elbow
      (olecranon), behind which passes the ulnar nerve; -- so
      called on account of the curiously painful tingling felt,
      when, in a particular position, it receives a blow; --
      called also {funny bone}.

   {Crazy quilt}, a bedquilt made of pieces of silk or other
      material of various sizes, shapes, and colors, fancifully
      stitched together without definite plan or arrangement.

Source : WordNet®

crazy bone
     n : a point on the elbow where the ulnar nerve passes near the
         surface; a sharp tingling sensation results when the
         nerve is knocked against the bone; "the funny bone is not
         humerus" [syn: {funny bone}]