Brown's game following European Commission (4)
I believe the answer is:
ecru
'brown's' is the definition.
(ecru is a kind of brown)
'game following european commission' is the wordplay.
'game' becomes 'ru' (rugby union).
'following' means one lot of letters go next to another.
'european commission' becomes 'ec'.
'ru' after 'ec' is 'ECRU'.
(Other definitions for ecru that I've seen before include "Very light brown colour" , "No bright colour" , "The Color" , "one of the colours" , "light beige" .)