lunatic vs crazy

lunatic and crazy both are nouns.

Word	Noun	Adjective	Verb	Adverb
lunatic	Yes	Yes	No	No
crazy	Yes	Yes	No	No

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

Other hyponyms of lunatic include looney, loony, nutcase, weirdo, bedlamite, pyromaniac, madwoman, madman.

lunatic (noun)	crazy (noun)
an insane person	someone deranged and possibly dangerous
a reckless impetuous irresponsible person

lunatic (adjective)	crazy (adjective)
insane and believed to be affected by the phases of the moon	intensely enthusiastic about or preoccupied with
	possessed by inordinate excitement
	foolish; totally unsound
	affected with madness or insanity
	bizarre or fantastic