Losing face, champion succeeded in love (4)
I believe the answer is:
eros
'in love' is the definition.
(I've seen this before)
'losing face champion succeeded' is the wordplay.
'losing face' means to remove the first letter.
'champion' becomes 'hero' (synonyms).
'succeeded' becomes 's' (genealogical abbreviation).
'hero' with its initial letter taken away is 'ero'.
'ero'+'s'='EROS'
(Other definitions for eros that I've seen before include "Name given to statue" , "Arrow-shooting god" , "Greek god of love - see statue in Piccadilly" , "Winged archer" , "Statue of love-god in Piccadilly Circus in London" .)