Immoral act ended in stir? (8)
I believe the answer is:
decadent
'immoral' is the definition.
(thesaurus)
'act ended in stir?' is the wordplay.
'in stir?' is an anagram indicator (I've seen 'in stir' mean this (I've seen this in other clues)).
'act'+'ended'='actended'
'actended' is an anagram of 'DECADENT'.
(Other definitions for decadent that I've seen before include "Showing moral decline" , "Reprobate" , "Fin-de-sicle" , "Culturally in decline" , "Degenerate" .)