What is Next Friend?

Legal Definition
In common law, a next friend (Law French prochain ami) is a person who represents another person who is under disability or otherwise unable to maintain a suit on his or her own behalf and who does not have a legal guardian. In England and Wales they are known as litigation friends. When a relative who is next of kin acts as a next friend for a person, that person is sometimes instead described as the natural guardian of the person. A next friend has full power over the proceedings in the action as if he or she were an ordinary plaintiff, until a guardian or guardian ad litem is appointed in the case; but the next friend is entitled to present evidence only on the same basis as any other witness.
-- Wikipedia
Legal Definition
Someone who appears in court in place of another who is not competent to do so, usually because they are a minor or are considered incompetent. Often the role is filled by a parent or other relative; it can be any legally-competent person whose interests do not run counter to those of the person on whose behalf they are acting . The "next friend" is not a party to the proceeding, nor are they a formally-appointed guardian. Instead, they are considered an agent of the court whose role is to protect the rights of the incompetent person.
Related terms
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Legal Definition
One who, without being regularly appointed guardian, acts for the benefit of an infant, married woman, or other person, not sui juris. Vide Amy; Prochein Amy.
-- Bouviers Law Dictionary
Legal Definition
The legal designation of the person by whom an infant or other person disabled from suing in his own name brings and prosecutes an action either at law or in equity; usually a relative. Strictly speaking, a next friend (or "prochein amy") is not appointed by the court to bring or maintain the suit, but is simply one who volunteers for that purpose, and is merely admitted or permitted to sue in behalf of the infant; but the practice of suing by a next friend has now been almost entirely superseded by the practice of appointing a guardian ad litem. See McKinney v. Jones, 55 Wis. 39, 11 N. W. 606; Guild v. Cranston, 8 Cusbu (Mass.) 506; Tucker v. Dabbs, l2 Heisk. (Tenn.) 18; Leopold v. Meyer, 10 Abb. Prae. (N. Y.) 40.
-- Black's Law Dictionary
Legal Definition
One who sues on behalf of an infant, a married woman, lunatic or other person who could not bring the action. See 134 U. S. 650; 33 L. Ed. 1047, 10 Sup. Ct. Rep. 638.
-- Ballentine's Law Dictionary