Rapper revised English in draft (7)
I believe the answer is:
prepare
'draft' is the definition.
(thesaurus)
'rapper revised english in' is the wordplay.
'revised' is an anagram indicator.
'english' becomes 'E' (abbreviation).
'in' indicates putting letters inside.
'rapper' anagrammed gives 'prpare'.
'prpare' placed around 'e' is 'PREPARE'.
(Other definitions for prepare that I've seen before include "get ready for something new" , "study" , "Make (something) ready" , "[GET READY] (3 of 3)" , "Make ready or suitable" .)