Swindles; castles (5)
I believe the answer is:
rooks
I believe this clue is a double definition.
'swindles' is the first definition.
(I know this)
'castles' is the second definition.
(I know this)
(Other definitions for rooks that I've seen before include "Collective name for them is a parliament" , "Chess castles and birds" , "Large, crow-like birds" , "men on the board" , "Cheats" .)