Writer's novel I want (5)
I believe the answer is:
twain
'writer's' is the definition.
(author Mark Twain)
'novel i want' is the wordplay.
'novel' indicates an anagram (letters in a new or novel order).
'i'+'want'='iwant'
'iwant' with letters rearranged gives 'TWAIN'.
(Other definitions for twain that I've seen before include "Mark . . . . . was the pen name of Samuel Langhorne Clemens" , "Two (arch.)" , "US author; pair (arch.)" , "Pair (archaic) - US novelist, Mark" , "A pen-name" .)