Cautioned about schooling (9)
I believe the answer is:
education
'schooling' is the definition.
(I've seen this before)
'cautioned about' is the wordplay.
'about' indicates anagramming the letters.
'cautioned' is an anagram of 'EDUCATION'.
(Other definitions for education that I've seen before include "Blair's triple mantra" , "Work of master" , "an answer to all clues, initially" , "Process of acquiring knowledge" , "Cautioned (anag)" .)