Good loser at game (5)
I believe the answer is:
sport
This clue is a double definition.
'good loser' is the first definition.
(thesaurus)
'game' is the second definition.
(I've seen this before)
'at' acts as a link.
(Other definitions for sport that I've seen before include "Exhibit publicly; eg soccer" , "Eg, football; fun" , "Physical activity" , "Wear - game - generous type" , "Show off" .)