Playing a nice tune, say (9)
I believe the answer is:
enunciate
'say' is the definition.
(I know that say can be written as enunciate)
'playing a nice tune' is the wordplay.
'playing' indicates an anagram.
'a'+'nice'+'tune'='anicetune'
'anicetune' anagrammed gives 'ENUNCIATE'.
(Other definitions for enunciate that I've seen before include "Clearly express" , "Utter" , "Say (something) clearly" , "State clearly or formally" , "Speak with precision" .)