Influential charm is employed so they receive teacher's approval, in short (11)
I believe the answer is:
charismatic
'influential' is the definition.
(thesaurus)
'charm is employed so they receive teacher's approval in short' is the wordplay.
I cannot really understand how this works, but
'charm' could be 'charisma' (I've seen this before) and 'charisma' is found in the answer.
The remaining letters 'tic' is a valid word which might be clued in a way I don't see.
This explanation may well be incorrect...
Can you help me to learn more?
(Other definitions for charismatic that I've seen before include "With a special ability to attract" , "Compellingly attractive" , "Charming" , "Having strongly attractive personal power" , "Inspirational in personality" .)