Lazy star on the radio (4)
I believe the answer is:
idle
'lazy' is the definition.
('idle' can be similar in meaning to 'lazy')
'star on the radio' is the wordplay.
'star' becomes 'idol' (idol is a kind of star).
'on the radio' shows a homophone (sound like).
'idol' sounds like 'IDLE'.
(Other definitions for idle that I've seen before include "Turn over" , "no longer employed?" , "Dormant" , "Do nothing, laze" , "Still" .)