Funds for the old writer, one being housed by offspring (8)
I believe the answer is:
pensions
'funds for the old' is the definition.
(old-age pensions)
'writer one being housed by offspring' is the wordplay.
'writer' becomes 'pen' (something which writes).
'one' becomes 'I' (Roman numeral).
'being housed by' means one lot of letters goes inside another.
'offspring' becomes 'sons' (offspring are one's children).
'i' placed inside 'sons' is 'sions'.
'pen'+'sions'='PENSIONS'
(Other definitions for pensions that I've seen before include "Payments in retirement, for continental boarding houses?" , "The benefits" , "income from these?" , "accommodation overseas?" , "Regular payments after retirement" .)