discolour[verb]Synonyms: stain, fade, mark, soil, streak, tarnish, tinge
[TahlilGaran] English Synonym Dictionary ▲
dis‧col‧our British English,
discolor American English /dɪsˈkʌlə $ -ər/
verb [intransitive and transitive] to change colour, or to make something change colour, so that it looks unattractive:
Once cut, apples quickly discolour. [TahlilGaran] Dictionary of Contemporary English ▲