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