Politician rambled after one recovered (8)
I believe the answer is:
improved
'recovered' is the definition.
(recover can mean to improve or convalesce)
'politician rambled after one' is the wordplay.
'politician' becomes 'MP' (Member of Parliament).
'rambled' becomes 'roved' ('rove' can be a synonym of 'ramble').
'after' means one lot of letters go next to another.
'one' becomes 'i' (Roman numeral).
'mp'+'roved'='mproved'
'mproved' put after 'i' is 'IMPROVED'.
(Other definitions for improved that I've seen before include "Made or got better" , "Made progress" , "Grew or made better" , "Became better" , "Made better in quality" .)