Routine garb for priest (5)
I believe the answer is:
habit
This might be a double definition.
'routine' is the first definition.
(I've seen this before)
'garb for priest' is the second definition.
'habit' can be an answer for 'garb' (habiting is a kind of garbing). I'm not certain of the 'for priest' bit.
Can you help me to learn more?
(Other definitions for habit that I've seen before include "Custom; riding dress" , "addictive practice" , "Settled practice" , "Breaking this is hard" , "Regular practice" .)