Go to be with girl at home (4)
I believe the answer is:
join
'go to be with' is the definition.
(to join someone is to go to be with them)
'girl at home' is the wordplay.
'girl' becomes 'jo' ().
'at home' becomes 'in' (similar in meaning).
'jo'+'in'='JOIN'
(Other definitions for join that I've seen before include "Sign up" , "Link, unite" , "Attach" , "Amalgamate" , "Enrol in" .)