Endurance game (8)
I believe the answer is:
patience
I believe this clue is a double definition.
'endurance' is the first definition.
(thesaurus)
'game' is the second definition.
(I've seen this before)
(Other definitions for patience that I've seen before include "Card came for one" , "Virtue - solitaire" , "capacity for endurance" , "Musical work" , "that one plays" .)