What is Excommunicato Interdicitur Omuls Actus Legitimus, Ita Quod Agere Non Potest, Nee Aliquem Convenire, Licet Ipse Ab Aliis Possit Conveniri?

Legal Definition
Co. Litt. 133. Every legal act is forbidden an excommunicated person, so that he cannot act, nor sue any person, but he may be sued by others.1
-- Black's Law Dictionary