Owing to student struggle (4)
I believe the answer is:
duel
'struggle' is the definition.
(I know that duel is a type of struggle)
'owing to student' is the wordplay.
'owing' becomes 'due' (similar in meaning).
'to' is a charade indicator (letters next to each other).
'student' becomes 'l' (learner, as in L-plates for learner drivers).
'due'+'l'='DUEL'
(Other definitions for duel that I've seen before include "Fight between two persons" , "Potentially fatal fight between two people" , "Combat between two people in matter of honour" , "Fight between two people over an affair of honour" , "Combat to settle a row" .)