Pull broadcast about artist - not singular (6)
I believe the answer is:
plural
'not singular' is the definition.
('plural' is the opposite to 'singular')
'pull broadcast about artist' is the wordplay.
'broadcast' indicates anagramming the letters (letters scattered or cast around).
'about' is an insertion indicator.
'artist' becomes 'RA' (Royal Academician, member of Royal Academy of Arts).
'pull' with letters rearranged gives 'plul'.
'plul' enclosing 'ra' is 'PLURAL'.
(Other definitions for plural that I've seen before include "Word ending in 'L' for words ending in 'S'?" , "Indicating more than one" , "Form of noun or verb in respect of more than one" , "Several" , "Word form denoting more than one is involved" .)