ostiary vs man of the cloth

ostiary and man of the cloth both are nouns.

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

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

ostiary: 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 ostiary include clergyman, reverend, Holy Order, Order.

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