Throw off one's game (5)
I believe the answer is:
addle
'throw off one's game' is the definition.
(I've seen this in another clue)
This is the entire clue.
(Other definitions for addle that I've seen before include "Muddle or confuse" , "(Of eggs) become rotten" , "Mix up or confuse" , "becomes muddled" , "Get rotten" .)