One not winning different roles (5)
I believe the answer is:
loser
'one not winning' is the definition.
(I've seen this before)
'different roles' is the wordplay.
'different' indicates an anagram (letters placed in a different order).
'roles' is an anagram of 'LOSER'.
(Other definitions for loser that I've seen before include "Defeated contestant" , "one that's been left behind" , "Winner's opponent" , "Defeated competitor" , "Unsuccessful competitor" .)