Leave and live having abandoned son (4)
I believe the answer is:
exit
'leave' is the definition.
('exit' can be a synonym of 'leave')
'live having abandoned son' is the wordplay.
'live' becomes 'exist' ('exist' can be a synonym of 'live').
'having abandoned' is a deletion indicator.
'son' becomes 's'.
'exist' with 's' taken out is 'EXIT'.
'and' acts as a link.
(Other definitions for exit that I've seen before include "Road leaving motorway" , "Departure of actor" , "Player's departure" , "Outlet" , "Withdrawal" .)