Patsy may be a twin (4)
I believe the answer is:
dupe
This clue is a double definition.
'patsy' is the first definition.
(thesaurus)
'a twin' is the second definition.
(thesaurus)
'may be' is the link.
(Other definitions for dupe that I've seen before include "Sucker" , "A cat's-paw" , "Swindle" , "Pawn, mug" , "Put one over on, cod" .)