Defends a politician wearing tight chinos (9)
I believe the answer is:
champions
'defends' is the definition.
('champion' can be a synonym of 'defend')
'a politician wearing tight chinos' is the wordplay.
'politician' becomes 'mp'.
'wearing' is an insertion indicator.
'tight' indicates an anagram (tight can mean drunk).
'a'+'mp'='amp'
'chinos' is an anagram of 'chions'.
'amp' going into 'chions' is 'CHAMPIONS'.
(Other definitions for champions that I've seen before include "Defends" , "Pinch Amos to find successful competitors" , "best ones" , "Winners in competition" , "They win first place in competitions" .)