Rubbish wagon returning with farm vehicle (7)
I believe the answer is:
tractor
'farm vehicle' is the definition.
(I've seen this in another clue)
'rubbish wagon returning' is the wordplay.
'rubbish' becomes 'rot' (both can mean nonsense).
'wagon' becomes 'cart' (cart is a kind of wagon).
'returning' says the letters should be written backwards.
'rot'+'cart'='rotcart'
'rotcart' written backwards gives 'TRACTOR'.
'with' is the link.
(Other definitions for tractor that I've seen before include "Agricultural vehicle" , "Farming vehicle" , "Vehicle used for hauling heavy loads" , "Bombardier possibly" , "Vehicle used on farms" .)