After dad's time (4)
I believe the answer is:
past
'after' is the definition.
(I've seen this in another clue)
'dad's time' is the wordplay.
'dad's' becomes 'pa's' (both can mean one's father).
'time' becomes 't' (abbreviation).
'pas'+'t'='PAST'
(Other definitions for past that I've seen before include "Beyond" , "Days gone by" , "The time that has elapsed" , "Gone by in time" , "historical times" .)