Struggle to learn ahead of examination (7)
I believe the answer is:
contest
'struggle' is the definition.
(thesaurus)
'learn ahead of examination' is the wordplay.
'learn' becomes 'con' (synonyms).
'ahead of' is a charade indicator (letters next to each other) (I've seen this in other clues).
'examination' becomes 'test' (synonyms).
'con'+'test'='CONTEST'
'to' acts as a link.
(Other definitions for contest that I've seen before include "Competition; dispute" , "Match" , "Tournament" , "Competition or conflict" , "Oppose - competition" .)