Feature of vehicle - it's green, novel (8)
I believe the answer is:
'feature of vehicle' is the definition.
(I've seen this before)
'it's green novel' is the wordplay.
'novel' indicates anagramming the letters.
'itsgreen' with letters rearranged gives 'STEERING'.
(Other definitions for steering that I've seen before include "-- Committee; -- wheel" , "Guiding or showing the way" , "Guiding and directing, say a car" , "Controlling the direction" , "Guiding, directing the course" .)