Heart of Darkness author (6)
I believe the answer is:
conrad
'heart of darkness author' is the definition.
(I've seen this before)
This is all the clue.
(Other definitions for conrad that I've seen before include "Author of Lord Jim" , "Heart of Darkness author" , "Joseph ...... wrote 'Lord Jim'" , "Joseph -, novelist (Heart of Darkness)" , "Joseph --, author" .)