Colour used by officer is excellent (6)
I believe the answer is:
cerise
'colour' is the definition.
(cerise is a kind of colour)
'used by officer is excellent' is the wordplay.
'used by' says the answer is hidden in the clue.
'CERISE' is hidden within 'officer is excellent'.
(Other definitions for cerise that I've seen before include "Colour of ripe cherries" , "Reddish-pink colour" , "Pinkish-red" , "Cherry-coloured" , "Vivid reddish-pink" .)