Cautioned about tuition (9)
I believe the answer is:
education
'tuition' is the definition.
(thesaurus)
'cautioned about' is the wordplay.
'about' indicates an anagram.
'cautioned' anagrammed gives 'EDUCATION'.
(Other definitions for education that I've seen before include "Process of acquiring knowledge" , "Cautioned (anag)" , "Theory and practice of teaching" , "Teaching process" , "New Labour mantra, when repeated" .)