Coloured part of the eye (4)
I believe the answer is:
iris
'coloured part of the eye' is the definition.
(I've seen this before)
This is the entire clue.
(Other definitions for iris that I've seen before include "bit of a looker" , "Plant - part of the eye" , "Flag - surrounding pupil" , "Part of the eye, usually brown or blue" , "Fleur-de-lys" .)