Wrong choice before important game (3,6)
I believe the answer is:
ice hockey
'game' is the definition.
(ice hockey is a kind of game)
'wrong choice before important' is the wordplay.
'wrong' indicates anagramming the letters.
'before' means one lot of letters go next to another.
'important' becomes 'key' ('key' can be similar in meaning to 'important').
'choice' is an anagram of 'icehoc'.
'icehoc'+'key'='ICE-HOCKEY'
(Other definitions for ice hockey that I've seen before include "Sport with puck" , "Violent sport, big in North America" , "Team game played with long sticks" , "Game played by skaters with a puck" .)