Horse-drawn vehicle withdrawn? (5)
I believe the answer is:
sulky
I believe this clue is a double definition.
'horse-drawn vehicle' is the first definition.
(I know that sulky is a type of horse-drawn vehicle)
'withdrawn?' is the second definition.
(both can mean moody or sullen)
(Other definitions for sulky that I've seen before include "Morose" , "Sullen" , "Petulant" , "Moody" .)