The handsome youth said no, unfortunately (6)
I believe the answer is:
adonis
'the handsome youth' is the definition.
(I've seen this before)
'said no unfortunately' is the wordplay.
'unfortunately' indicates anagramming the letters.
'said'+'no'='saidno'
'saidno' is an anagram of 'ADONIS'.
(Other definitions for adonis that I've seen before include "Beautiful Greek youth" , "lovely chap" , "Said no to the Greek youth" , "Most 8 Greek youth" , "Beautiful young man" .)