Of a racial group (6)
I believe the answer is:
ethnic
'of a racial group' is the definition.
(I've seen this before)
This is all the clue.
(Other definitions for ethnic that I've seen before include "Of the distinct ways of living of a particular group of people" , "Exotic" , "Relating to groups with common customs" , "To do with race or nationality" , "Relating to national and cultural origins" .)