ticket taker vs doorman

ticket taker and doorman both are nouns.

Word	Noun	Adjective	Verb	Adverb
ticket taker	Yes	No	No	No
doorman	Yes	No	No	No

As nouns, doorman is a hypernym of ticket taker; that is, doorman is a word with a broader meaning than ticket taker:

ticket taker: someone who is paid to admit only those who have purchased tickets
doorman: someone who guards an entrance

Other hypernyms of ticket taker include door guard, doorkeeper, gatekeeper, hall porter, ostiary, porter.

ticket taker (noun)	doorman (noun)
someone who is paid to admit only those who have purchased tickets	someone who guards an entrance