Journalist has penned awfully drab sort of book (8)
I believe the answer is:
hardback
'sort of book' is the definition.
(I've seen this before)
'journalist has penned awfully drab' is the wordplay.
'journalist' becomes 'hack' (I've seen this before).
'has penned' means one lot of letters goes inside another (inserted letters are enclosed or penned in).
'awfully' indicates anagramming the letters.
'drab' with letters rearranged gives 'rdba'.
'hack' enclosing 'rdba' is 'HARDBACK'.
(Other definitions for hardback that I've seen before include "Book with board covers" , "Penguins are rarely so" , "Sort of book" , "Durable version of book" , "It might be a novel!" .)