Parsing inflected forms may not always work as expected. If the following does not give the correct word, try Latin Words or Perseus.
littĕrārĭus (lītĕr-), a, um, adj. [littera], of or belonging to reading and writing: ludus, an elementary school, Quint. 1, 4, 27; Tac. A. 3, 66; Plin. 9, 8, 8, § 25; Suet. Calig. 45: magister. an elementary teacher, schoolmaster, Vop. Pertin. 8.