Earlier head of religious house (5)
I believe the answer is:
prior
I believe this clue is a double definition.
'earlier' is the first definition.
(synonyms)
'head of religious house' is the second definition.
(I've seen this before)
(Other definitions for prior that I've seen before include "Preceding" , "Previous; deputy abbot" , "English keeper" , "figure of authority in retreat" , "writer of epigrammatic verse" .)