Taught nothing revolutionary after expression of disapproval (7)
I believe the answer is:
tutored
'taught' is the definition.
(synonyms)
'nothing revolutionary after expression of disapproval' is the wordplay.
'nothing' becomes 'o' (looks like zero - 0).
'revolutionary' becomes 'red'.
'after' is a charade indicator (letters next to each other).
'expression of disapproval' becomes 'tut' (I've seen this before).
'o'+'red'='ored'
'ored' put after 'tut' is 'TUTORED'.
(Other definitions for tutored that I've seen before include "Taught small groups" , "Coached" , "Gave private lessons to" , "Privately taught" , "Trained" .)