Bore pilot silly, which is novel (9)
I believe the answer is:
potboiler
'is novel' is the definition.
(potboiler can mean a commercial novel)
'bore pilot silly' is the wordplay.
'silly' indicates anagramming the letters.
'bore'+'pilot'='borepilot'
'borepilot' is an anagram of 'POTBOILER'.
'which' acts as a link.
(Other definitions for potboiler that I've seen before include "Book written just for the money" , "Inferior art or literary work produced chiefly for money" , "Literary work of poor quality" , "Nice little earner" , "hasty work" .)