Parts with a wayward loser (5)
I believe the answer is:
roles
'parts' is the definition.
(parts in a play)
'a wayward loser' is the wordplay.
'a wayward' is an anagram indicator.
'loser' anagrammed gives 'ROLES'.
'with' is the link.
(Other definitions for roles that I've seen before include "Dramatic parts" , "Parts in plays" , "Theatrical parts" , "Actors' parts" , "Parts in a play" .)