Forceful novel is involved with it (7)
I believe the answer is:
violent
'forceful' is the definition.
(I've seen this before)
'novel is involved with it' is the wordplay.
'is involved with' indicates an anagram (involved can mean confusing or complex).
'novel' anagrammed with 'it' can make 'VIOLENT'.
(Other definitions for violent that I've seen before include "Tending to use intimidatory force" , "Wild - not evil (anag)" , "not peaceful either" , "Intensely forceful" , "Marked by physical force" .)