Liberal suffering decline (8)
I believe the answer is:
languish
'decline' is the definition.
(I know that languish is a more specific form of degenerate)
'liberal suffering' is the wordplay.
'liberal' becomes 'l' (abbreviation).
'suffering' becomes 'anguish' (anguish is a kind of suffering).
'l'+'anguish'='LANGUISH'
(Other definitions for languish that I've seen before include "fade away" , "Become discouraged" , "Haul sign away - lack vitality" , "lose strength" , "Long" .)