Laundry problem
I believe the answer is:
stain
'laundry problem' is the definition.
(I've seen this in another clue)
This is the entire clue.
(Other definitions for stain that I've seen before include "Blemish; colour (wood)" , "Discolouring mark" , "Satin (anag.)" , "Discoloration" , "Discoloured patch" .)