ostiarius vs clergyman

ostiarius and clergyman both are nouns.

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

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

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

ostiarius (noun)	clergyman (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