Of a cultural group (6)
I believe the answer is:
ethnic
'of a cultural group' is the definition.
(I've seen this in another clue)
This is all the clue.
(Other definitions for ethnic that I've seen before include "Denoting origin by descent" , "Characteristic of a certain culture" , "Of the distinct ways of living of a particular group of people" , "from a particular community" , "Having a common race or cultural tradition" .)