Cyril makes up a song (5)
I believe the answer is:
lyric
'a song' is the definition.
(song with lyrics)
'cyril makes up' is the wordplay.
'makes up' indicates anagramming the letters.
'cyril' is an anagram of 'LYRIC'.
(Other definitions for lyric that I've seen before include "Short poem of songlike quality" , "Part of a libretto" , "Poem - verse - London theatre" , "Expressing the poet's emotions" , "in musical" .)