Studied diverse novel (7)
I believe the answer is:
revised
'studied' is the definition.
Both the definition and answer are adjectives. Perhaps there's an association between them I don't understand?
'diverse novel' is the wordplay.
'novel' indicates an anagram (letters in a new or novel order).
'diverse' with letters rearranged gives 'REVISED'.
Can you help me to learn more?
(Other definitions for revised that I've seen before include "Diverse (anag.)" , "Swotted for an exam" , "Changed and improved" , "Altered" , "Prepared for exams" .)