Rugby (6)
I believe the answer is:
rugger
'rugby' is the definition.
(synonyms)
This is the entire clue.
(Other definitions for rugger that I've seen before include "Oval-ball game, colloquially" , "Game played with an oval ball (informal)" , "Team sport, informally" , "... (union) players playing this (colloquially)" , "Kind of football (informal)" .)