What is Excommunicato Interdictur Omnis Actus Legitimus, Ita Quod Agere Non Potest, Nec Aliquem Convenire, Licet Ipse Ab Aliis Possit Conveniri?

Legal Definition
An excommunicato interdictur omnls actus legitimus, its quod agere non potest, nee aliquem convenire, licet ipse ab aliis possit convenlri is a writ which issued out of chancery to prohibit an excommunicated person from every legal act, so that he cannot act, nor sue any person, but he may be sued by others.
-- Wikipedia
Legal Definition
Every legal act is forbidden one excommunicated, so that he cannot act, nor can he sue anyone, but he can be sued himself by others.
-- Ballentine's Law Dictionary