Complacent broadcast feels as if it’s beginning to decline (4-9)
I believe the answer is:
self-satisfied
'complacent' is the definition.
(I know that complacent can be written as self-satisfied)
'broadcast feels as if it's beginning to decline' is the wordplay.
'broadcast' is an anagram indicator (letters scattered or cast around).
'beginning to' suggests taking the first letters.
The first letter of 'decline' is 'd'.
'feels'+'as'+'if'+'its'='feelsasifits'
'feelsasifits' anagrammed gives 'selfsatisfie'.
'selfsatisfie'+'d'='SELF-SATISFIED'
(Another definition for self-satisfied that I've seen is " Smug".)