Writer is back on benefit (7)
I believe the answer is:
pension
'benefit' is the definition.
(thesaurus)
'writer is back on' is the wordplay.
'writer' becomes 'pen' (something which writes).
'back' is a reversal indicator.
'is' back-to-front is 'si'.
'pen'+'si'+'on'='PENSION'
(Other definitions for pension that I've seen before include "Retirement pay in a Continental boarding-house" , "support for the elderly" , "Regular payment received after retirement" , "Payment to retired persons a continental boarding house" , "Retiree's income" .)