A competition, as opposed to an exam (7)
I believe the answer is:
contest
'a competition' is the definition.
('contest' can be a synonym of 'competition')
'opposed to an exam' is the wordplay.
'opposed to' becomes 'con' (I've seen this in another clue).
'an exam' becomes 'test' (synonyms).
'con'+'test'='CONTEST'
'as' acts as a link.
(Other definitions for contest that I've seen before include "Oppose - competition" , "Match" , "Competition; dispute" , "Competition or conflict" , "Tournament" .)