In Scottish law (now historical ): a person who performed the duties of tutor or guardian towards a minor without having been legally appointed to do so. Also (in some civil codes): a person who oversees a tutor or guardian.
The old Scottish common law relating to the guardianship of children was abolished by statute in 1986..
Origin
Mid 17th century. From pro- + tutor. Compare classical Latin prōtūtor, French protuteur.