Fabric discoloration (5)
I believe the answer is:
stain
'fabric discoloration' is the definition.
(I've seen this in another clue)
This is all the clue.
(Other definitions for stain that I've seen before include "Dirty mark; dye" , "Mark with colour, dirt" , "Blemish; colour (wood)" , "Taint" , "Colour, dye" .)