Vegetable in the vehicle, and rubbish (6)
I believe the answer is:
carrot
'vegetable' is the definition.
(I know that carrot is a type of root vegetable)
'vehicle and rubbish' is the wordplay.
'vehicle' becomes 'car' (car is a kind of vehicle).
'and' means one lot of letters go next to another.
'rubbish' becomes 'rot' (both can mean nonsense).
'car'+'rot'='CARROT'
'in the' acts as a link.
(Other definitions for carrot that I've seen before include "Rewarding vegetable?" , "Red vegetable used as inducement" , "Incentive (but not the stick)" , "Orange vegetable" , "Vegetable - incentive" .)