The outback is in open country, you need a car (5)
I believe the answer is:
motor
'car' is the definition.
(motor can informally mean a car)
I don't understand how the remainder of the clue works.
Can you help me to learn more?
(Other definitions for motor that I've seen before include "Drive" , "Driver" , "Make good progress" , "Wheels" , "Travel by car, engine" .)