1540s, from Modern Latin Jesuita, member of the Societas Jesu ("Society of Jesus"), founded 1533 by Ignatius Loyola to combat Protestantism. See Jesus. Their enemies (in both Catholic and Protestant lands) accused them of belief that ends justify means, hence the sense "a crafty or dissembling person" (1630s), and jesuitical "deceitful, designing, insinuating" (1610s).