a member of a Roman Catholic congregation of contemplative religious promoting devotion to the Passion of Jesus: the congregation, founded (1720) in Italy, engages chiefly in missionary work
See Passionist in American Heritage Dictionary 4
(păshˈə-nĭst)
noun
A member of a Roman Catholic religious order founded in Italy in 1720 by Saint Paul of the Cross (1694-1775) and dedicated to promoting devotion to the Passion of Christ chiefly by missionary work.