Designer Chanel (4)
I believe the answer is:
'designer chanel' is the definition.
(I've seen this in another clue)
This is all the clue.
(Other definitions for coco that I've seen before include "Gabrielle Bonheur Chanel" , "address for Chanel" , "Famous clown" , "French fashion designer, who branched into perfume etc" , "'... the Clown, ... Chanel (4)'" .)