Audible greeting for spectator (7)
I believe the answer is:
watcher
'spectator' is the definition.
(thesaurus)
I don't understand the rest of the clue.
Can you help me to learn more?
(Other definitions for watcher that I've seen before include "One who observes" , "I observe" , "Onlooker" , "Alert observer" , "Big Brother?" .)