Victor’s opposition to new roles (5)
I believe the answer is:
Here is my best explanation:
'victor's opposition' is the definition.
The definition and answer can be both people as well as being singular nouns.
Maybe you can see an association between them that I don't see?
'new roles' is the wordplay.
'new' indicates anagramming the letters.
'roles' with letters rearranged gives 'LOSER'.
'to' is the link.
(Other definitions for loser that I've seen before include "Unsuccessful person", "one that's been left behind", "Flop", "An also-ran", "Non-achiever", "Failed competitor", "Defeated competitor", "lemon", "Non-winner" and "A failure, also-ran".)