Cop, say, getting agitated about last part of controversial Caribbean song (7)
I believe the answer is:
calypso
'caribbean song' is the definition.
(I've seen this before)
'cop say getting agitated about last part of controversial' is the wordplay.
'getting agitated' is an anagram indicator.
'about' means one lot of letters goes inside another.
'last part of' indicates one should take the final letters.
The last letter of 'controversial' is 'l'.
'cop'+'say'='copsay'
'copsay' is an anagram of 'caypso'.
'caypso' enclosing 'l' is 'CALYPSO'.
(Other definitions for calypso that I've seen before include "Caribbean dance" , "Satirical West Indian song and dance" , "Gk. nymph; Caribbean ballad" , "W. Indian ballad" , "West Indian ballad - Homerian sea nymph" .)