Square vehicle (4)
I believe the answer is:
quad
I believe this clue is a double definition.
'square' is the first definition.
(quad can mean a square space)
'vehicle' is the second definition.
(I have seen 'sporty vehicle' mean 'quad' so perhaps 'vehicle' could also mean 'quad')
(Other definitions for quad that I've seen before include "sporty vehicle" , "Square amid buildings" , "yard" , "space found in building" , "Court" .)