Heard rumours about what auditor needs (7)
I believe the answer is:
'what auditor needs' is the definition.
(an eardrum is needed to hear things)
'heard rumours about' is the wordplay.
'about' says the answer is hidden in the clue (the clue goes around or about the answer).
'EARDRUM' is hidden within 'heard rumours'.
(Other definitions for eardrum that I've seen before include "One hears" , "Organ membrane" , "Ear membrane" , "Hearing membrane" , "Listener partly" .)