Game and horse trials (9)
I believe the answer is:
badminton
'game' is the definition.
(badminton is a kind of game)
I cannot understand how the remainder of the clue works.
Can you help me to learn more?
(Other definitions for badminton that I've seen before include "Game with shuttlecocks" , "Game played with a shuttlecock" , "Court game" , "Game using shuttlecock" , "in which rackets are involved" .)