Black friar, Blackfriar n. (Eccl.) A friar of the Dominican order, so named because wearing the black mantle of the Dominicans; called also predicant and preaching friar; in France, Jacobin. Also, sometimes, a Benedictine.
... staring sad-eyed into the hurrying waters of the brook, there came to him the clicking of sandalled feet, and glancing up, he beheld one clad as a black friar. A fat man he was, jolly of figure and mightily round; his nose was bulbous and he ... — Beltane The Smith • Jeffery Farnol