Returned a novel about very intrepid sort (10)
I believe the answer is:
adventurer
'intrepid sort' is the definition.
(I know that adventurer are usually audacious)
'returned a novel about very' is the wordplay.
'novel' indicates an anagram (letters in a new or novel order).
'about' is an insertion indicator.
'very' becomes 'v' (abbreviation).
'returned'+'a'='returneda'
'returneda' is an anagram of 'adenturer'.
'adenturer' placed around 'v' is 'ADVENTURER'.
(Other definitions for adventurer that I've seen before include "mercenary" , "Speculator" , "An opportunist" , "One loving dangerous exploits" , "hero?" .)