Mark off for student who passed out (8)
I believe the answer is:
graduate
I believe this clue is a double definition.
'mark off' is the first definition.
(graduate can mean to mark off or grade)
'student who passed out' is the second definition.
(student who passed their exams)
'for' acts as a link.
(Other definitions for graduate that I've seen before include "progress" , "Holder of university degree" , "Person holding university degree" , "Gain degree" , "Scholar" .)