Band unsettling priest (6)
I believe the answer is:
stripe
'band' is the definition.
('stripe' can be a synonym of 'band')
'unsettling priest' is the wordplay.
'unsettling' indicates an anagram.
'priest' is an anagram of '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" .)