ostiary vs clergyman

ostiary and clergyman both are nouns.

Word	Noun	Adjective	Verb	Adverb
ostiary	Yes	No	No	No
clergyman	Yes	No	No	No

As nouns, clergyman is a hypernym of ostiary; that is, clergyman 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
clergyman: a member of the clergy and a spiritual leader of the Christian Church

Other hypernyms of ostiary include man of the cloth, reverend, Holy Order, Order.

ostiary (noun)	clergyman (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