Endlessly applaud one in concert broadcast (8)
I believe the answer is:
proclaim
'broadcast' is the definition.
(thesaurus)
I don't understand the remainder of the clue.
Can you help me to learn more?
(Other definitions for proclaim that I've seen before include "Make a public announcement" , "Reveal" , "shout from the housetops" , "Broadcast" , "Speak out" .)