Of the pontiff (5)
I believe the answer is:
papal
'of the pontiff' is the definition.
(I've seen this in another clue)
This is all the clue.
(Other definitions for papal that I've seen before include "Of the highest Vatican authority" , "Relating to the Pontiff" , "of Catholic high-up" , "Of the RC leader" , "Relating to the Pope" .)