I condemn a terrible authority (9)
I believe the answer is:
dominance
'authority' is the definition.
('dominance' can be a synonym of 'authority')
'i condemn a terrible' is the wordplay.
'terrible' indicates an anagram.
'i'+'condemn'+'a'='icondemna'
'icondemna' anagrammed gives 'DOMINANCE'.
(Other definitions for dominance that I've seen before include "top position" , "Supremacy" , "Mastery" , "Commanding position" , "Control - ascendency" .)