Give up supporting game (5)
I believe the answer is:
forgo
'give up' is the definition.
('forgo' can be a synonym of 'give up')
'supporting game' is the wordplay.
'supporting' becomes 'for'.
'game' becomes 'go' (go is a kind of game).
'for'+'go'='FORGO'
(Other definitions for forgo that I've seen before include "Waive" , "pass up" , "Live without" , "Sacrifice" , "Go without (something)" .)