discolouration vs appearance

discolouration and appearance both are nouns.

Word	Noun	Adjective	Verb	Adverb
discolouration	Yes	No	No	No
appearance	Yes	No	No	No

As nouns, appearance is a hypernym of discolouration; that is, appearance is a word with a broader meaning than discolouration:

Other hypernyms of discolouration include visual aspect.

discolouration (noun)	appearance (noun)
the act of changing the natural color of something by making it duller or dingier or unnatural or faded	the act of appearing in public view
a soiled or discolored appearance	formal attendance (in court or at a hearing) of a party in an action
	pretending that something is the case in order to make a good impression
	outward or visible aspect of a person or thing
	a mental representation
	the event of coming into sight