impractical vs crazy

impractical is not a noun while crazy is a noun.

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

impractical (noun)	crazy (noun)
	someone deranged and possibly dangerous

impractical (adjective)	crazy (adjective)
not practical; not workable or not given to practical matters	intensely enthusiastic about or preoccupied with
not practical or realizable; speculative	possessed by inordinate excitement
	foolish; totally unsound
	affected with madness or insanity
	bizarre or fantastic