Deny struggling with Melancholy and Indolence initially, performing as a handsome youth (8)
I believe the answer is:
endymion
'a handsome youth' is the definition.
(figure of Greek myth)
'deny struggling with melancholy and indolence initially performing' is the wordplay.
'struggling' indicates an anagram.
'with melancholy' becomes 'm' (I am not sure about this - if you are sure you should give a lot more credence to this answer).
'and' says to put letters next to each other.
'initially' says to take the initial letters.
'performing' becomes 'on' (as in being on stage).
The first letter of 'indolence' is 'i'.
'deny' with letters rearranged gives 'endy'.
'endy'+'m'+'i'+'on'='ENDYMION'
'as' is the link.
(Other definitions for endymion that I've seen before include "story of Keats" , "Moon lover; Keats poem" , "Handsome youth" , "Handsome shepherd of myth" , "Work by Keats" .)