Some stars are irritating on the radio show (5,4)
I believe the answer is:
great bear
'some stars' is the definition.
(constellation Ursa Major)
'irritating on the radio show' is the wordplay.
'irritating' becomes 'grate' (I've seen this before).
'on the radio' indicates a 'sounds like' (homophone) clue.
'show' becomes 'bear' (I've seen this before).
'grate' is a homophone of 'great'.
'great'+'bear'='GREAT BEAR'
'are' acts as a link.
(Other definitions for great bear that I've seen before include "Large animal - same as 7" , "visible in the night sky" , "Major stars" , "Ursa Major" , "'Large ursine in the heavens (5,4)'" .)