Former abbot's deputy (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)
'abbot's deputy' is the second definition.
(I've seen this before)
(Other definitions for prior that I've seen before include "Abbott's deputy being earlier?" , "Former - churchman" , "Coming before in time or importance" , "Senior monk; earlier" , "Deputy head of an abbey" .)