Finish with student loan (4)
I believe the answer is:
lend
'loan' is the definition.
(I know that loan can be written as lend)
'finish with student' is the wordplay.
'finish' becomes 'end' (synonyms).
'with' means one lot of letters go next to another.
'student' becomes 'l' (as in L-plates for learner drivers).
'end' after 'l' is 'LEND'.
(Other definitions for lend that I've seen before include "Supply (money) at interest" , "Give temporarily" , "Let someone borrow" , "Offer" , "Give on condition of return" .)