Showing displeasure with a vehicle (5)
I believe the answer is:
sulky
'vehicle' is the definition.
(sulky is a kind of vehicle)
I don't understand how the rest of the clue works.
Can you help me to learn more?
(Other definitions for sulky that I've seen before include "Moody" , "Sullen" , "Petulant" , "Morose" .)