Novel hat (6)
I believe the answer is:
trilby
This clue is a double definition.
'novel' is the first definition.
(I've seen this before)
'hat' is the second definition.
(trilby is a kind of hat)
(Other definitions for trilby that I've seen before include "It was felt to provide capital cover" , "Man's soft felt hat" , "Style of hat" , "Type of hat" , "Indented felt hat" .)