One drives over hill in fog (8)
I believe the answer is:
motorist
'one drives' is the definition.
(I've seen this before)
'hill in fog' is the wordplay.
'hill' becomes 'tor' (tor is a kind of hill).
'in' indicates putting letters inside.
'fog' becomes 'moist' (I can't explain this - if you can you should give a lot more credence to this answer).
'tor' going inside 'moist' is 'MOTORIST'.
'over' is the link.
Can you help me to learn more?
(Other definitions for motorist that I've seen before include "One relying on car" , "Woman taking mini" , "One driving" , "One on the road" , "Car-driver" .)