define psycho
Psycho is defined as someone or something that is crazy or insane. Stalking your ex-lover and killing his family pet is an example of behavior that would be described as psycho. noun. The definition of a psycho is slang for a crazy or insane person. An obsessed stalker who threatens to kill his ex-lover is an example of someone who is psycho. Psycho is defined as mind or mental. An example of psycho used as a prefix is in the word psychology, which means the study of the mind. , pl. -Â·chos. Informal psychotic, psychopathic, psychopath, and, earlier, psychoneurotic. the mind or mental processes: psychology, psychogenesis.