/ Dictionary / Index M M'Naghten test: Meaning and Definition of Find definitions for: M'Nagh'ten test" Pronunciation: (muk-nôt'n), [key] a rule that defines a person as legally insane when that person cannot distinguish right from wrong. Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease. M.N.A. M.N.A.S. Related Content Daily Word Quiz: clairvoyant Analogy of the Day: Today’s Analogy Spelling Bee: Today’s Spelling Bee Frequently Misspelled Words Frequently Mispronounced Words Easily Confused Words Writing & Language