ostiarius vs man of the cloth

ostiarius and man of the cloth both are nouns.

Word	Noun	Adjective	Verb	Adverb
ostiarius	Yes	No	No	No
man of the cloth	Yes	No	No	No

As nouns, man of the cloth is a hypernym of ostiarius; that is, man of the cloth is a word with a broader meaning than ostiarius:

ostiarius: the lowest of the minor Holy Orders in the unreformed Western Church but now suppressed by the Roman Catholic Church
man of the cloth: a member of the clergy and a spiritual leader of the Christian Church

Other hypernyms of ostiarius include clergyman, reverend, Holy Order, Order.

ostiarius (noun)	man of the cloth (noun)
the lowest of the minor Holy Orders in the unreformed Western Church but now suppressed by the Roman Catholic Church	a member of the clergy and a spiritual leader of the Christian Church