Irish Protestant’s rank in Arabian sultanate (9)
I believe the answer is:
orangeman
'irish protestant's' is the definition.
(I've seen this before)
'rank in arabian sultanate' is the wordplay.
'rank' becomes 'range' (synonyms).
'in' means one lot of letters goes inside another.
'arabian sultanate' becomes 'Oman' (Oman is ruled by a sultan).
'range' placed into 'oman' is 'ORANGEMAN'.
(Other definitions for orangeman that I've seen before include "Religious society member" , "Member of a Protestant Irish society" , "Northern Ireland Protestant" , "one used to marching?" .)