Committee's not interested in discussion (5)
I believe the answer is:
board
'committee's' is the definition.
(board is a kind of committee)
'not interested in discussion' is the wordplay.
'not interested' becomes 'bored' ('bore' is the opposite to 'interest').
'in discussion' shows a homophone (sound like).
'bored' sounds like 'BOARD'.
(Other definitions for board that I've seen before include "panel" , "See 9" , "Plank" , "Collection of directors" , "Strip of timber" .)