Student had meal but not on time (4)
I believe the answer is:
late
'not on time' is the definition.
(I've seen this before)
'student had meal' is the wordplay.
'student' becomes 'l' (as in L-plates for learner drivers).
'had meal' becomes 'ate' (to have a meal is to eat).
'l'+'ate'='LATE'
'but' is the link.
(Other definitions for late that I've seen before include "after the sell-by date?" , "Teal (anag.)" , "Yet to arrive?" , "Behind schedule" , "Far on in the day" .)