Cyril's lost for words (5)
I believe the answer is:
lyric
'words' is the definition.
('lyric' can be a synonym of 'words')
'cyril's lost' is the wordplay.
'lost' indicates an anagram.
'cyril' with letters rearranged gives 'LYRIC'.
'for' is the link.
(Other definitions for lyric that I've seen before include "something to sing about? On the contrary" , "in musical" , "Words to a song" , "Of poetry that expresses thoughts and feelings" , "Text of a popular song" .)