Forget a French student with merit (7)
I believe the answer is:
unlearn
'forget' is the definition.
(unlearning is a kind of forgeting)
'a french student with merit' is the wordplay.
'a french' becomes 'un' ('a' in French).
'student' becomes 'l' (as in L-plates for learner drivers).
'with' means one lot of letters go next to another.
'merit' becomes 'earn' (I've seen this before).
'un'+'l'+'earn'='UNLEARN'
(Other definitions for unlearn that I've seen before include "Deliberately forget" , "Cease to hold (previous teaching)" , "Try to forget something" .)