Trip over loose boot in game (8)
I believe the answer is:
football
'game' is the definition.
(I know that football is a type of football codes)
'trip over loose boot' is the wordplay.
'trip' becomes 'fall' (trip can mean to fall over).
'over' means one lot of letters goes inside another.
'loose' is an anagram indicator (letters are loosened from their original positions).
'boot' anagrammed gives 'ootb'.
'fall' enclosing 'ootb' is 'FOOTBALL'.
'in' acts as a link.
(Other definitions for football that I've seen before include "Lob aloft poorly for this game" , "Gambling on soccer results" , "Liverpool or Everton, for example" , "controversial issue" , "See 20" .)