Of or pertaining to one of several ecclesiastics named Clement, especially— St. Clement, bishop of Rome in the first century;Pope Clement V. (1305–1314);Clement VII. (1378–1394), the first of the antipopes of Avignon.n. One of a series of compilations attributed to St. Clement.n. plural That part of the body of canon law which contains the collections made by Pope Clement V. of the acts of the Council of Vienne, a. d. 1311–12, with the addition of some of his decretals.n. A follower of, or a believer in the authority of, the antipope Clement VII.n. Same as methylene-violet.