Sisters seen in Vatican, unsurprisingly (4)
I believe the answer is:
nuns
'sisters' is the definition.
(I've seen this before)
'in vatican unsurprisingly' is the wordplay.
'in' indicates the answer is hidden within the clue.
'NUNS' is hidden in the letters of 'vatican unsurprisingly'.
'seen' is the link.
(Other definitions for nuns that I've seen before include "Retired women" , "women in order" , "Religious sisters" , "Convent residents" , "Holy sisters" .)