Archdeacon is operating game (7)
I believe the answer is:
venison
'game' is the definition.
(thesaurus)
'archdeacon is operating' is the wordplay.
'archdeacon' becomes 'ven'.
'operating' becomes 'on' (I've seen this in other clues).
'ven'+'is'+'on'='VENISON'
(Other definitions for venison that I've seen before include "Game" , "Meat - in ovens (anag)" , "Deer meat" , "Type of meat" , "Deer (as food)" .)