Rip-off artist finally duped novelist (6)
I believe the answer is:
conrad
'novelist' is the definition.
(I've seen this before)
'rip-off artist finally duped' is the wordplay.
'rip off' becomes 'con' (conning is a kind of ripping off).
'artist' becomes 'RA' (Royal Academician, member of Royal Academy of Arts).
'finally' indicates one should take the final letters.
The last letter of 'duped' is 'd'.
'con'+'ra'+'d'='CONRAD'
(Other definitions for conrad that I've seen before include "Joseph ...... wrote 'Lord Jim'" , "Joseph -, novelist (Heart of Darkness)" , "Joseph ---, Polish-born novelist" , "Heart of Darkness author" , "Author of Lord Jim" .)