Lecherous boxing champion (4)
I believe the answer is:
hero
'champion' is the definition.
(synonyms)
'lecherous boxing' is the wordplay.
'boxing' indicates a hidden word (the solution is contained or boxed up by the clue).
'HERO' is hidden in the letters of 'lecherous'.
(Other definitions for hero that I've seen before include "Admired champion" , "Leander's love" , "Principal male character in a play, movie, novel or poem" , "Leander's lover, who committed suicide when he drowned" , "paragon" .)