the world > matter > colour > change of colour > change colour of [verb (transitive)] > discolour (5)
transitive. To alter the usual or natural colour of; esp. to cause (a thing) to change to a less attractive, duller, or less natural colour; to spoil…
transitive. To discolour; figurative to stain.
= discolour, v. (obsolete).
transitive. = discolour, v. 1a, 2.
transitive. To remove the colour from; to make colourless or pale. Also: to spoil the colour of, to discolour.