Broadcast publicity in a Brazilian city (5)
I believe the answer is:
radio
'broadcast' is the definition.
(radio broadcast is a kind of broadcast)
'publicity in a brazilian city' is the wordplay.
'publicity' becomes 'ad' (advert).
'in' is an insertion indicator.
'a brazilian city' becomes 'rio' (I've seen this before).
'ad' inserted within 'rio' is 'RADIO'.
(Other definitions for radio that I've seen before include "It used to be called the wireless" , "Sound receiver" , "MW, LW or FM sound source" , "Communicate with" , "means of communication" .)