Typical American university student is after top grade (5)
I believe the answer is:
usual
'typical' is the definition.
(I've seen this before)
'american university student is after top grade' is the wordplay.
'american' becomes 'us' (abbreviation for United States).
'university' becomes 'u' (abbreviation for university).
'student' becomes 'l' (as in L-plates for learner drivers).
'is after' is a charade indicator (letters next to each other).
'top grade' becomes 'A' (top academic grade).
'l' put after 'a' is 'al'.
'us'+'u'+'al'='USUAL'
(Other definitions for usual that I've seen before include "Typical" , "Unexceptional" , "Customary, routine" , "Normal, customary" , "Normally done" .)