Morse, cop playing Wagner perhaps (8)
I believe the answer is:
composer
'wagner perhaps' is the definition.
(wagner is a kind of composer)
'morse cop playing' is the wordplay.
'playing' indicates an anagram.
'morse'+'cop'='morsecop'
'morsecop' anagrammed gives 'COMPOSER'.
(Other definitions for composer that I've seen before include "Person who writes music" , "Creative musician" , "he makes notes" , "Person creating original score" , "Writer of music" .)