crazy vs brainsick

crazy is a noun but brainsick is not a noun.

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

As adjectives, crazy and brainsick are synonyms defined as:

Other synonyms of crazy include demented, disturbed, mad, sick, unbalanced, unhinged.

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

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