PAs etc. cavorting around degenerate observer (9)
I believe the answer is:
spectator
'observer' is the definition.
(I know that spectator is a type of observer)
'pas etc cavorting around degenerate' is the wordplay.
'cavorting' is an anagram indicator.
'around' says the letters should be written backwards.
'degenerate' becomes 'rot' (rotting is a kind of degenerating).
'rot' in reverse letter order is 'tor'.
'pas'+'etc'='pasetc'
'pasetc' with letters rearranged gives 'specta'.
'specta'+'tor'='SPECTATOR'
(Other definitions for spectator that I've seen before include "Eyewitness, viewer" , "one's seen on the terraces?" , "Watcher" , "weekly magazine?" , "found on the terraces?" .)