noun
(slang) An insane person.
adjective
(slang) Crazy, insane.
(psychiatry, slang) Involving or pertaining to schizophrenia (in the medical sense); schizophrenic.
(slang, loosely, uncommon) Of a situation: odd, bizarre.
verb
(intransitive, slang) To act in an erratic and unpredictable manner; to go insane; to exhibit symptoms of schizophrenia.