One that studies and settles cases of conscience. It is said that Escobar has made a collection of the opinions of all the casuists before him. M. Le Feore, preceptor of Louis XIII. called the books of the casuists the art of quibbling with God; which does not seem far from truth, by reason of the multitude of distinctions and sublicties they abound with. Mayer has published a bibliotheca of casuists, containing an account of all the writers on cases of conscience, ranged under three heads; at first comprehending the Lutheran, the second the Calvinist, and the third the Romish casuists.