M'Naghten test

noun
M'Naght·​en test | \ mək-ˈnät-ᵊn- \

Legal Definition of M'Naghten test

: a standard under which a criminal defendant is considered to have been insane at the time of an act (as a killing) if he or she did not know right from wrong or did not understand the moral nature of the act because of a mental disease or defect

called also M'Naghten rule

— compare diminished capacity, durham rule, irresistible impulse test, substantial capacity test

Note: Many jurisdictions have followed the Model Penal Code in basing criminal insanity on either of two factors: an inability to appreciate the wrongfulness of an act, which reflects the influence of the M'Naghten test, or an inability to conform one's behavior to the dictates of the law, which reflects the concept of the irresistible impulse. Both factors must be rooted in a mental disease or defect, which is also what the Durham rule requires of insanity.

History and Etymology for M'Naghten test

after Daniel M'Naghten, defendant in 1843 murder case heard before the British House of Lords who was acquitted due to his insanity

Keep scrolling for more

Learn More about M'Naghten test

Cite this Entry

“M'Naghten test.” Merriam-Webster.com Legal Dictionary, Merriam-Webster, https://www.merriam-webster.com/legal/M%27Naghten%20test. Accessed 4 Jul. 2020.

Comments on M'Naghten test

What made you want to look up M'Naghten test? Please tell us where you read or heard it (including the quote, if possible).

WORD OF THE DAY

See Definitions and Examples »

Get Word of the Day daily email!

Test Your Vocabulary

A More Exception(al) Quiz

  • hot dog  hot dog  hot dog  hot dog cat
  • Which of the following words is not a synonym for ‘a young person’?
Spell It

Can you spell these 10 commonly misspelled words?

TAKE THE QUIZ
Bee Cubed

Test Your Knowledge - and learn some interesting things along the way.

TAKE THE QUIZ
Love words? Need even more definitions?

Subscribe to America's largest dictionary and get thousands more definitions and advanced search—ad free!