Rapper's critics (8)

I believe the answer is:

knockers

I believe this is a double definition.

'rapper's' is the first definition.
(I know this)

'critics' is the second definition.
(I've seen this before)

(Other definitions for knockers that I've seen before include "Critics" , "those delivering rap" , "those rapping" , "They criticise" .)

I've seen this clue in the Sydney Morning Herald.

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