Officials to ensure fair play (8)
I believe the answer is:
referees
'officials to ensure fair play' is the definition.
(I've seen this before)
This is the entire clue.
(Other definitions for referees that I've seen before include "Arbiters, often in sport" , "Umpires" , "Arbiters as in soccer" , "Officials to ensure fair play" , "Sports officials" .)