Be aware of refusal being broadcast (4)
I believe the answer is:
know
'be aware of' is the definition.
(thesaurus)
'refusal being broadcast' is the wordplay.
'refusal' becomes 'no'.
'being broadcast' shows a homophone (sound like) (how the word might sound on the radio or TV).
'no' sounds like 'KNOW'.
(Other definitions for know that I've seen before include "Be aware of (something)" , "Be familiar with" , "Be acquainted with" , "Be sure of something" , "Understand" .)