Novel spread fear with hound (7-2)
I believe the answer is:
unheard-of
'novel' is the definition.
(thesaurus)
'spread fear with hound' is the wordplay.
'spread' indicates an anagram.
'with' is a charade indicator (letters next to each other).
'fear'+'hound'='fearhound'
'fearhound' is an anagram of 'UNHEARD-OF'.
(Other definitions for unheard-of that I've seen before include "Fear hound being not previously known" , "Without precedent" , "Unknown - novel" , "Previously unknown" , "Inconceivable" .)