Band unsettling priest (6)
I believe the answer is:
stripe
'band' is the definition.
(I know that band can be written as stripe)
'unsettling priest' is the wordplay.
'unsettling' indicates anagramming the letters.
'priest' with letters rearranged gives 'STRIPE'.
(Other definitions for stripe that I've seen before include "Length of material, maybe showing rank" , "bar" , "Chevron on a uniform to denote military rank" , "24 across (anag)" , "Band of colour - 3 of rank" .)