Appearance in average broadcast (4)
I believe the answer is:
mien
'appearance' is the definition.
(thesaurus)
'average broadcast' is the wordplay.
'average' becomes 'mean' (type of average).
'broadcast' shows a homophone (sound like) (how the word might sound on the radio or TV).
'mean' is a homophone of 'MIEN'.
'in' is the link.
(Other definitions for mien that I've seen before include "Counterance - mine?" , "attitude" , "A countenance like mine" , "Bearing, demeanour" , "Appearance, bearing" .)