Splotch (5)
I believe the answer is:
stain
'splotch' 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 "Blot" , "Discolouring mark" , "Smear" , "Discoloured mark" , "Blemish; colour (wood)" .)