discolourise vs discolor

discolourise and discolor both are verbs.

Word	Noun	Adjective	Verb	Adverb
discolourise	No	No	Yes	No
discolor	No	No	Yes	No

As verbs, discolor is a hypernym of discolourise; that is, discolor is a word with a broader meaning than discolourise:

discolourise (verb)	discolor (verb)
cause to become white or lighter in color	change color, often in an undesired manner
	lose color or turn colorless
	cause to lose or change color