Mustang, for one (6)
'mustang for one' is the definition.
(mustang is a kind of equine)
This is the entire clue.
(Other definitions for equine that I've seen before include "Like horses" , "Relating to horses" , "Like a horse" , "Horse or donkey, perhaps" , "Resembling a horse" .)
(Other definitions for car that I've seen before include "Hatchback, say?" , "Wheeled vehicle" , "One for the road?" , "Personal vehicle" , "Private vehicle" .)