Degenerate is loudest when drunk (9)
I believe the answer is:
dissolute
'degenerate' is the definition.
('dissolute' can be a synonym of 'degenerate')
'is loudest when drunk' is the wordplay.
'when drunk' is an anagram indicator (I've seen this in other clues).
'is'+'loudest'='isloudest'
'isloudest' with letters rearranged gives 'DISSOLUTE'.
(Other definitions for dissolute that I've seen before include "O, lust dies when one is this loose in morals" , "Old tissue (anag) - like a rake?" , "Duelist so (anag) - debauched" , "Sensually overindugent" , "Sensually overindulgent" .)