Old man's first in school for exam result (4)
I believe the answer is:
pass
'result' is the definition.
'old man's first in school' is the wordplay.
'old man's' becomes 'pa's' (both can mean someone's father).
'first in school' becomes 's' (1st letter of 'school').
'pas'+'s'='PASS'
'for exam' acts as a link.
This may not be correct. Some or all of it may be part of another bit of the clue.
Can you help me to learn more?
(Other definitions for pass that I've seen before include "beats me" , "good performance by exam candidate" , "Graduate, perhaps? A" , "Gesture to hypnotise" , "Succeed; overtake" .)