Colour used by Spencer is extraodinary (6)
I believe the answer is:
cerise
'colour' is the definition.
(I know that cerise is a type of red)
'used by spencer is extraodinary' is the wordplay.
'used by' indicates the answer is hidden within the clue.
'CERISE' is hidden within 'spencer is extraodinary'.
(Other definitions for cerise that I've seen before include "Vivid reddish-pink" , "Light red colour" , "Cherry red colour" , "Pinkish red" , "Reddish-pink colour" .)