Feature of vehicle - it's green, novel (8)
I believe the answer is:
steering
'feature of vehicle' is the definition.
(I've seen this before)
'it's green novel' is the wordplay.
'novel' indicates anagramming the letters.
'its'+'green'='itsgreen'
'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" .)