Greek god left in a game (6)
I believe the answer is:
apollo
'greek god' is the definition.
(Apollo is an example)
'left in a game' is the wordplay.
'left' becomes 'l' (common abbreviation).
'in' means one lot of letters goes inside another.
'game' becomes 'polo' (polo is a kind of game).
'a'+'polo'='apolo'
'l' placed inside 'apolo' is 'APOLLO'.
(Other definitions for apollo that I've seen before include "handsome youth" , "Lad who's striking" , "American space programme for landing men on moon" , "Programme targeting satellite" , "God of light and US space programme" .)