How to say crazy person in English?

fool English [fu:l] American [ful]

Third person singular: fools Third person plural: fools Present participle: fooling Past participle: fooled Past tense: fooled

Basic explanation of fool

Noun fool, fool; deceived; person with quirks; person who is fooled

Transitive verb fool, deceive; waste, waste; make trouble joke; idleness

Intransitive verb to deceive; to joke; to tease

Adjective stupid; silly