Handsome young man (6)
I believe the answer is:
adonis
<span class="explanation-format__ClueExplanation">'<span class="explanation-format__original">handsome young man</span>' is the definition.<br/ ><span class="explanation-format__explanation">(I've seen this before)</span><br/ ><br/ >This is all the clue.<br/ ></span>
(Other definitions for adonis that I've seen before include "A very good-looking ancient Greek" , "Handsome youth loved by Aphrodite" , "Extremely attractive young man from Greek mythology" , "extremely handsome chap" , "A very handsome legendary Greek" .)