Fool’s under pressure to overtake (4)
I believe the answer is:
Here is my best explanation:
'overtake' is the definition.
('pass' can be a synonym of 'overtake')
'fool's under pressure' is the subsidiary indication.
'fool's' becomes 'ass' (ass is a kind of fool).
'under' says to put letters next to each other.
'pressure' becomes 'p' (abbreviation).
'ass' after 'p' is 'pass'.
'to' is the link.
(Other definitions for pass that I've seen before include "Authorise; overtake", "Pronounce (judgement)", "Overtake; mountain way", "Col", "Overtake - get through", "Go beyond; fail to answer", "Blow over", "Succeed; overtake", "Route over a mountain" and "Exam success".)