One hears/ heard rumours in part (7)
I believe the answer is:
eardrum
'one hears' is the definition.
(I've seen this before)
'heard rumours in part' is the wordplay.
'in part' says the answer is hidden in the clue.
'EARDRUM' is hidden within 'heard rumours'.
(Other definitions for eardrum that I've seen before include "hearing part" , "Vibrating membrane in the head" , "Ear membrane" , "Otic membrane" , "Listener partly" .)