An abrasive comedian (5)
I believe the answer is:
emery
I believe this clue is a double definition.
'an abrasive' is the first definition.
(thesaurus)
'comedian' is the second definition.
(I have seen 'old comedian' mean 'emery' so perhaps 'comedian' could also mean 'emery')
(Other definitions for emery that I've seen before include "old comedian" , "Hard black-grey mineral used in grinding and polishing" , "Black abrasive" , "Abrasive powder" , "Dick - - , late comedian" .)