Reporter’s test of hearing (5)
I believe the answer is:
aural
'of hearing' is the definition.
(aural means relating to hearing)
'reporter's test' is the wordplay.
'reporter's' shows a homophone (sound like) (report can mean to speak something aloud).
'test' becomes 'oral' (oral is a type of examination).
'oral' sounds like 'AURAL'.
(Other definitions for aural that I've seen before include "To do with hearing or the ears" , "musical perception" , "Relating to sense of hearing" , "Received by the ears" , "of air" .)