Source : Webster's Revised Unabridged Dictionary (1913)

Discolor \Dis*col"or\, v. t. [imp. & p. p. {Discolored}; p. pr.
   & vb. n. {Discoloring}.] [OE. descolouren, OF. descolorer, F.
   d['e]colorer, fr. L. dis- + cololare, coloratum, to color,
   color color. See {Color}.] [Written also {discolour}.]
   1. To alter the natural hue or color of; to change to a
      different color; to stain; to tinge; as, a drop of wine
      will discolor water; silver is discolored by sea water.

   2. To alter the true complexion or appearance of; to put a
      false hue upon.

            To discolor all your ideas.           --Wat??

Source : WordNet®

discolour
     v : change color, often in an undesired manner; "The shirts
         discolored" [syn: {discolor}, {colour}, {color}]