The one who writes the words of songs (8)
I believe the answer is:
lyricist
'the one who writes the words of songs' is the definition.
(I've seen this before)
This is the entire clue.
(Other definitions for lyricist that I've seen before include "Word-writer for songs" , "Writer of the words of a song" , "Musical words writer" , "Sit Cyril down - he's a songwriter" , "Writer of words for songs" .)