Couple on the radio distressed chum? That’s excessive (3,4)
I believe the answer is:
too much
'excessive' is the definition.
(I've seen this before)
'couple on the radio distressed chum?' is the wordplay.
'couple' becomes 'two' (two people or things).
'on the radio' shows a homophone (sound like).
'distressed' is an anagram indicator.
'two' is a homophone of 'too'.
'chum' is an anagram of 'much'.
'too'+'much'='TOO MUCH'
'that's' acts as a link.
(Other definitions for too much that I've seen before include "More than is tolerable" , "More than enough" , "See 17" , "American expression of approval" , "Excess, more than is needed" .)