followers vs multitude

followers and multitude both are nouns.

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

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

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

followers (noun)	multitude (noun)
a group of followers or enthusiasts	a large gathering of people
	the common people generally
	a large indefinite quantity