Ridicule a politician, a silly person outwardly (7)
I believe the answer is:
lampoon
'ridicule' is the definition.
(lampooning is a kind of ridiculing)
'a politician a silly person outwardly' is the wordplay.
'politician' becomes 'mp'.
'a silly person' becomes 'loon'.
'outwardly' is an insertion indicator.
'a'+'mp'='amp'
'amp' going into 'loon' is 'LAMPOON'.
(Other definitions for lampoon that I've seen before include "Personal satire" , "Parody" , "Written ridicule of polo man" , "Ridicule with satire" , "Pool man (anag)" .)