Loser sent parts (5)
I believe the answer is:
roles
'parts' is the definition.
(parts in a play)
'loser sent' is the wordplay.
'sent' indicates anagramming the letters (send can mean to excite or stimulate).
'loser' anagrammed gives 'ROLES'.
(Other definitions for roles that I've seen before include "Dramatic parts" , "Parts in a play" , "Parts in plays" , "Theatrical parts" , "Actors' parts" .)