Poem disturbed Cyril (5)
I believe the answer is:
lyric
'poem' is the definition.
(I know that lyric is a type of poem)
'disturbed cyril' is the wordplay.
'disturbed' indicates anagramming the letters (the order of letters is disturbed).
'cyril' is an anagram of 'LYRIC'.
(Other definitions for lyric that I've seen before include "Expressing the poet's emotions" , "Poem - verse - London theatre" , "Part of a libretto" , "Of poetry that expresses thoughts and feelings" , "having a light quality" .)