Ridicule a boring liberal politician with nothing on (7)
I believe the answer is:
lampoon
'ridicule' is the definition.
(lampooning is a kind of ridiculing)
'a boring liberal politician with nothing on' is the wordplay.
'boring' indicates putting letters inside (to bore something can mean to drill into it).
'liberal' becomes 'l' (abbreviation).
'politician' becomes 'MP' (Member of Parliament).
'with' says to put letters next to each other.
'nothing' becomes 'O' (looks like zero - 0).
'l'+'mp'='lmp'
'a' inserted within 'lmp' is 'lamp'.
'lamp'+'o'+'on'='LAMPOON'
(Other definitions for lampoon that I've seen before include "ridiculous scenario" , "Literary satire" , "Written ridicule of polo man" , "Mock" , "Pool man (anag)" .)