med. jur. A disease of the mind, which is differently defined as it applies to a class of disorders, or only to one species of them. As a general term it includes all the varieties of mental, disorders, not fatuous. 2. Lunacy is adopted as a general term, on account of its general use as such in various legislative acts and legal proceedings, as commissions of lunacy, and in this sense it seems to be synonymous with non compos mentis, or of unsound mind. 3. In a more restricted sense, lunacy is the state of one who has bad understanding, but by disease, grief, or other accident, has lost the use of reason.
Law Dictionary – Alternative Legal Definition
Lunacy is that condition or habit in which the mind is directed by the will, but is wholly or partially misguided or erroneously governed by it; or it is the impairment of any one or more of the faculties of the mind, accompanied with or inducing a defect in the comparing faculty. Owings’ Case, 1 Bland (Md.) 386, 17 Am. Dec. 311. See Insanity. Inquisition (or inquest) of lunacy. A quasi judicial examination into the sanity or insanity of a given person, ordered by a court having jurisdiction, on a proper application and sufficient preliminary showing of facts, held by the sheriff (or marshal, or a magistrate, or the court itself, according to the local practice) with the assistance of a special jury, usually of six men, who are to hear evidence and render a verdict in accordance with the facts. This is the usual foundation for an order appointing a guardian or conservator for a person adjudged to be insane, or for committing him to an insane asylum