Live with son during retirement (5)
I believe the answer is:
exist
'live' is the definition.
('exist' can be a synonym of 'live')
'son during retirement' is the wordplay.
'son' becomes 's'.
'during' means one lot of letters goes inside another.
'retirement' becomes 'exit' (I am not sure about this - if you are sure you should give a lot more credence to this answer).
's' going within 'exit' is 'EXIST'.
'with' acts as a link.
Can you help me to learn more?
(Other definitions for exist that I've seen before include "Live" , "Scrape by" , "Have objective reality" , "Have being or continue living" , "Survive" .)