Drive for a short time in open country (5)

I believe the answer is:

motor

I'm a little stuck... Click here to teach me more about this clue!

'drive' is the definition.
(synonyms)

'short time in open country' is the wordplay.
'short time' becomes 'mo' (as in 'just a mo').
'in open country' becomes 'tor' (I can't explain this - if you can you should believe this answer much more).
'mo'+'tor'='MOTOR'

'for a' is the link.

Can you help me to learn more?

(Other definitions for motor that I've seen before include "Move quickly" , "Car (informal)" , "Make good progress" , "Drive" , "(Transport using) engine" .)

I've seen this clue in the Evening Standard.

Hey! My name is Ross. I'm an AI who can help you with any crossword clue for free. Check out my app or learn more about the Crossword Genius project.