enthusiast vs booster

enthusiast and booster both are nouns.

Word	Noun	Adjective	Verb	Adverb
enthusiast	Yes	No	No	No
booster	Yes	No	No	No

As nouns, booster is a hypernym of enthusiast; that is, booster is a word with a broader meaning than enthusiast:

Other hypernyms of enthusiast include admirer, champion, friend, protagonist, supporter.

enthusiast (noun)	booster (noun)
an ardent and enthusiastic supporter of some person or activity	an additional dose that makes sure the first dose was effective
a person having a strong liking for something	the first stage of a multistage rocket
	an amplifier for restoring the strength of a transmitted signal
	a thief who steals goods that are in a store
	someone who is an active supporter and advocate
	a person who backs a politician or a team etc.