A mental defect or disease that makes it impossible for a person to understand the wrongfulness of his acts or, even if he understands them, to ditinguish right from wrong.
If anyone is charge with a crime and is found to be criminally insane they cannot be convicted of the crime.
The character Jack Torrance from the Shining was criminally insane.
a person who exhibits actions that could be a potential danger to him/herself or others.
The murderer was criminally insane.