Don't answer, overtake (4)
I believe the answer is:
pass
I believe this clue is a double definition.
'don't answer' is the first definition.
(as in passing in a quiz)
'overtake' is the second definition.
(as in passing on a road)
(Other definitions for pass that I've seen before include "Elapse; mountain route" , "Approve; mountain route" , "good performance by exam candidate" , "Go by; mountain route" , "I've no idea" .)