Express disapproval and educate vacuous student (5)
I believe the answer is:
tutee
'student' is the definition.
(someone being tutored)
'express disapproval and educate vacuous' is the wordplay.
'express disapproval' becomes 'tut' (tutting is making a disapproving sound).
'and' is a charade indicator (letters next to each other).
'vacuous' says to hollow out the word (remove centre letters).
'educate' with its centre removed is 'ee'.
'tut'+'ee'='TUTEE'
(Other definitions for tutee that I've seen before include "One learns from a personal teacher" , "Student, pupil" .)