Hindered one politician with a terrible deed (7)
I believe the answer is:
impeded
'hindered' is the definition.
('impede' can be a synonym of 'hinder')
'one politician with a terrible deed' is the wordplay.
'one politician' becomes 'imp' (I've seen this in other clues**).
'with' is a charade indicator (letters next to each other).
'a terrible' indicates an anagram.
'deed' is an anagram of 'eded'.
'imp'+'eded'='IMPEDED'
(Other definitions for impeded that I've seen before include "Obstructed" , "Held up" , "Hindered, slowed down" , "Got in the way of" , "Hindered progress" .)