Cloister head (6)
I believe the answer is:
abbess
'cloister head' is the definition.
(I've seen this in another clue)
This is all the clue.
(Other definitions for abbess that I've seen before include "Superior of group of nuns" , "She heads a religious community" , "superior to her sisters!" , "Head of group of nuns" , "Person in charge of convent" .)