Cyril confused by nearly everything poetic (7)
I believe the answer is:
lyrical
'poetic' is the definition.
(I've seen this before)
'cyril confused by nearly everything' is the wordplay.
'confused' indicates anagramming the letters.
'by' is a charade indicator (letters next to each other).
'nearly' means to remove the last letter.
'everything' becomes 'all' (all things).
'all' with its final letter taken away is 'al'.
'cyril' anagrammed gives 'lyric'.
'lyric'+'al'='LYRICAL'
(Other definitions for lyrical that I've seen before include "Relating to song's words" , "Using poetic language, wax thus (7)" , "Highly enthusiastic" , "Effusive" , "it can be waxed" .)