ostiary vs door guard

ostiary and door guard both are nouns.

Word	Noun	Adjective	Verb	Adverb
ostiary	Yes	No	No	No
door guard	Yes	No	No	No

As nouns, ostiary and door guard are synonyms defined as:

Other synonyms of ostiary include doorkeeper, doorman, gatekeeper, hall porter, porter.

ostiary (noun)	door guard (noun)
someone who guards an entrance	someone who guards an entrance
the lowest of the minor Holy Orders in the unreformed Western Church but now suppressed by the Roman Catholic Church