Quite a few school leavers (7)
I believe the answer is:
several
'quite a few' is the definition.
(I've seen this before)
'school leavers' is the wordplay.
'school' indicates anagramming the letters (school can mean to improve or manipulate).
'leavers' with letters rearranged gives 'SEVERAL'.
(Other definitions for several that I've seen before include "three or four" , "Sundry, distinct" , "Various, sundry" , "A good few" , "Assorted" .)