Approach game with reversed wordplay (3-2)
I believe the answer is:
run-up
'approach' is the definition.
(I know that run-up is a type of approach)
'game with reversed wordplay' is the wordplay.
'game' becomes 'RU' (rugby union).
'with' means one lot of letters go next to another.
'reversed' says the letters should be written backwards.
'wordplay' becomes 'pun' (synonyms).
'pun' written backwards gives 'nup'.
'ru'+'nup'='RUN-UP'
(Other definitions for run-up that I've seen before include "Bowler's approach?" , "Cricketing approach?" , "Approach - preliminaries" , "Preliminary period" .)