McNaughton rules

noun

A test of criminal insanity by which "it must be clearly proved that, at the time of committing the act, the party accused was labouring under such a defect of reason, from disease of the mind, as not to know the nature and quality of the act he was doing, or, if he did know it, that he did not know he was doing what was wrong".

Ask AI about this wordChatGPTClaudePerplexityGoogle AIGrok

Meanings

nounMcNaughton rules pl (plural only)

alternative M'Naghten rule

  1. pluralplural onlycriminal lawA test of criminal insanity by which "it must be clearly proved that, at the time of committing the act, the party accused was labouring under such a defect of reason, from disease of the mind, as not to know the nature and quality of the act he was doing, or, if he did know it, that he did not know he was doing what was wrong".

Origin

1843, from the trial of Daniel McNaughton, who shot and murdered Edward Drummond, the Private Secretary to the then British Prime Minister Sir Robert Peel.

Full word history & related roots →
Cite this entry
APA

McNaughton rules. (n.d.). In WatkinsX Dictionary. Retrieved November 4, 2026, from https://dictionary.watkinsx.com/word/McNaughton%20rules

MLA

“McNaughton rules.” WatkinsX Dictionary, https://dictionary.watkinsx.com/word/McNaughton%20rules. Accessed November 4, 2026.

Chicago

WatkinsX Dictionary, s.v. “McNaughton rules,” accessed November 4, 2026, https://dictionary.watkinsx.com/word/McNaughton%20rules.

Source: McNaughton rules on Wiktionary, CC BY-SA 4.0.