- (in English law) a set of rules established by the case of Regina v. McNaughten (1843) by which legal proof of insanity in the commission of a crime depends upon whether or not the accused can show either that they did not know what they were doing or that they are incapable of realizing that what they were doing was wrong
Collins Concise English Dictionary © HarperCollins Publishers::
McNaughten Rules, McNaghten Rules /məkˈnɔːtən/ pl n