Resident, as it happens, at home (4-2)
I believe the answer is:
live-in
'resident' is the definition.
(I've seen this before)
'as it happens at home' is the wordplay.
'as it happens' becomes 'live' (as in live broadcasting).
'at home' becomes 'in' ('I'm in' can mean 'I'm at home').
'live'+'in'='LIVE-IN'
(Other definitions for live-in that I've seen before include "Resident at one's place of work" , "(Of employee or lover) resident" .)