laity vs multitude

laity and multitude both are nouns.

Word	Noun	Adjective	Verb	Adverb
laity	Yes	No	No	No
multitude	Yes	No	No	No

As nouns, multitude is a hypernym of laity; that is, multitude is a word with a broader meaning than laity:

laity: in Christianity, members of a religious community that do not have the priestly responsibilities of ordained clergy
multitude: the common people generally

Other hypernyms of laity include hoi polloi, mass, masses, people, the great unwashed.

laity (noun)	multitude (noun)
in Christianity, members of a religious community that do not have the priestly responsibilities of ordained clergy	a large gathering of people
	the common people generally
	a large indefinite quantity