Copy machine powder (5)
I believe the answer is:
toner
'copy machine powder' is the definition.
(I've seen this in another clue)
This is the entire clue.
(Other definitions for toner that I've seen before include "Powder used in printers" , "Lotion for cleansing the skin" , "Copier powder" , "Material for printer" , "Chemical solution used to soften colours" .)