cas·u·ist / ˈkazhoōist/ • n. a person who uses clever but unsound reasoning, esp. in relation to moral questions; a sophist. ∎  a person who resolves moral problems by the application of theoretical rules to particular instances.DERIVATIVES: cas·u·is·tic / ˌkazhoōˈistik/ adj.cas·u·is·ti·cal / ˌkazhoōˈistikəl/ adj.cas·u·is·ti·cal·ly adv.

casuist student of cases of conscience. XVII. — F. casuiste — Sp. (modL.) casuista, f. L. cāsus CASE 1; see -IST.
Hence casuistry XVIII; prob. after sophistry, and so at first derogatory.