enthusiast vs maniac

enthusiast and maniac both are nouns.

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

As nouns, maniac is a hyponym of enthusiast; that is, maniac is a word with a more specific, narrower meaning than enthusiast:

enthusiast: a person having a strong liking for something
maniac: a person who has an obsession with or excessive enthusiasm for something

Other hyponyms of enthusiast include animal fancier, bird fancier, technophile.

enthusiast (noun)	maniac (noun)
an ardent and enthusiastic supporter of some person or activity	an insane person
a person having a strong liking for something	a person who has an obsession with or excessive enthusiasm for something

enthusiast (adjective)	maniac (adjective)
	wildly disordered