Lewis & Short

littĕrĭo (lītĕr-), ōnis, m. [litterae], a language-master, in a contemptuous sense: appellare (aliquem) loquacem talpam, et purpuratam simiam, et litterionem Graecum, Amm. 17, 11, 1; so, Graecus, Aug. adv. Leg. et Proph. 1, § 52.