Former head of a religious order (5)
I believe the answer is:
prior
I believe this is a double definition.
'former' is the first definition.
(both can mean at earlier time)
'head of a religious order' is the second definition.
(I've seen this before)
(Other definitions for prior that I've seen before include "Coming before N a superior" , "Former - holy man" , "Deputy head of an abbey" , "Coming before in time or importance" , "More pressing" .)