National sporting fixture on the radio (4)
I believe the answer is:
thai
'national' is the definition.
('Thai' is an example)
'sporting fixture on the radio' is the wordplay.
'sporting fixture' becomes 'tie' (a tie is a sports match).
'on the radio' shows a homophone (sound like).
'tie' sounds like 'THAI'.
(Other definitions for thai that I've seen before include "East Asian" , "National" , "Sort of massage" , "Easterner" , "Native of Southeast Asia" .)