Study opening into nunnery (7)
I believe the answer is:
convent
'nunnery' is the definition.
(I've seen this in another clue)
'study opening' is the wordplay.
'study' becomes 'con' (con can informally mean to study).
'opening' becomes 'vent' (vent is a kind of opening).
'con'+'vent'='CONVENT'
'into' acts as a link.
(Other definitions for convent that I've seen before include "Building for nuns" , "Religious community" , "place for nuns" , "Religious house" , "Nunnery" .)