Vitandus

A vitandus (Latin for "one to be avoided") excommunicate was someone affected by a rare and grave form of excommunication, in which the Church ordered, as a remedial measure, that the faithful were not to associate with him "except in the case of husband and wife, parents, children, servants, subjects", and in general unless there was some reasonable excusing cause.A Modern Catholic Dictionary (1980)
It thus imposed a form of shunning somewhat similar to Jewish cherem.
Since the coming into effect of the 1983 Code of Canon Law, this form of excommunication is no longer envisaged in the canon law of the Catholic Church. The 1917 Code still included it, imposing it automatically (a latae sententiae excommunication) on anyone who did physical violence to the Pope himself,Canon 2343 §1 1 of the 1917 Code of Canon Law and declaring that, with that one exception, "nobody is a vitandus excommunicate unless the Apostolic See has excommunicated him by name and has proclaimed the excommunication publicly and in the decree has stated expressly that he must be avoided".Canon 2258 §2 of the 1917 Code of Canon Law 
The distinction between a vitandus and a toleratus ("tolerated") excommunicate was introduced `for the first time by Pope Martin V in 1418.
The most notable case in the 20th century of excommunication with the effect of making the person a vitandus was that of the priest Alfred Loisy.
In 1950, antipope Michel Collin announced that he had taken the name Clement XV.Michael W. Cuneo: The Smoke of Satan: Conservative and Traditionalist Dissent in Contemporary American Catholicism (JHU Press, 1999 ISBN 0801862655, 9780801862656), pp. 121–134 Pope Pius XII reduced him to the lay state in 1951Time magazine, Pope Clement XV (15 March 1971) and publicly declared him by name a vitandus excommunicate.
==References==
Category:Canon law (Catholic Church)
Category:Punishments in religion