doorman vs doorkeeper

doorman and doorkeeper both are nouns.

Word	Noun	Adjective	Verb	Adverb
doorman	Yes	No	No	No
doorkeeper	Yes	No	No	No

As nouns, doorman and doorkeeper are synonyms defined as:

Other synonyms of doorman include door guard, gatekeeper, hall porter, ostiary, porter.

doorman (noun)	doorkeeper (noun)
someone who guards an entrance	someone who guards an entrance
	an official stationed at the entrance of a courtroom or legislative chamber
	the lowest of the minor Holy Orders in the unreformed Western Church but now suppressed by the Roman Catholic Church