Hue changer (4)
I believe the answer is:
dyer
'hue changer' is the definition.
(I've seen this in another clue)
This is the entire clue.
(Other definitions for dyer that I've seen before include "Also a cleaner, probably" , "Colourer (of clothes, perhaps)" , "One colouring e.g. fabric" , "Fabric colourer" , "Increase (in output)" .)