Income from a boarding house (7)
I believe the answer is:
pension
I believe this is a double definition.
'income' is the first definition.
(I have seen 'Retired income ' mean 'pension' so perhaps 'income' could also mean 'pension')
'a boarding house' is the second definition.
(I've seen this before)
'from' acts as a link.
(Other definitions for pension that I've seen before include "Bed and breakfast or small hotel in France" , "Retired person's allowance" , "support for the elderly" , "Retirement allowance" , "Retiree's income" .)