A role in “Separated” (5)
I believe the answer is:
apart
'separated' is the definition.
(synonyms)
'a role' is the wordplay.
'role' becomes 'part' (eg a part or role in a film).
'a'+'part'='APART'
'in' is the link.
(Other definitions for apart that I've seen before include "Cut off - in pieces" , "away" , "Estranged - in pieces" , "First Christmas present from my love" , "set aside" .)