Damn shame pleb’s on the loose (9)
I believe the answer is:
blaspheme
'damn' is the definition.
(thesaurus)
'shame pleb's on the loose' is the wordplay.
'on the loose' is an anagram indicator.
'shame'+'pleb'='shamepleb'
'shamepleb' with letters rearranged gives 'BLASPHEME'.
(Other definitions for blaspheme that I've seen before include "Speak profanely" , "Curse, profane" , "Speak irreverently about God" , "Say irreverent things about God" , "Talk irreverently about God and sacred things" .)