crazy vs screwball

crazy and screwball both are nouns.

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

As adjectives, crazy and screwball are synonyms defined as:

Other synonyms of crazy include half-baked, softheaded.

crazy (noun)	screwball (noun)
someone deranged and possibly dangerous	a pitch with reverse spin that curves toward the side of the plate from which it was thrown
	a whimsically eccentric person

crazy (adjective)	screwball (adjective)
intensely enthusiastic about or preoccupied with	foolish; totally unsound
possessed by inordinate excitement
foolish; totally unsound
affected with madness or insanity
bizarre or fantastic