psycho

A person who is psychotic or otherwise insane.

“The loony bin up on the hill is full of psychos.”

A person who acts in a bizarre or dangerous manner.

“She complained that he was a psycho for driving at such a high speed in heavy traffic.”

Psychotic, or otherwise insane.

A class, at a college or university, in which psychology is taught.

“I've got anthro, socio, lunch, and psycho.”