Spoilt brat's broadcast (8)
I believe the answer is:
impaired
'spoilt' is the definition.
('impair' can be a synonym of 'spoil')
'brat's broadcast' is the wordplay.
'brat' becomes 'imp'.
'broadcast' becomes 'aired' ('aired' can be a synonym of 'broadcast').
'imp'+'aired'='IMPAIRED'
(Other definitions for impaired that I've seen before include "Defective" , "hurt" , "Had negative impact" , "casued damage" , "Spoilt" .)