Lewis & Short

Parsing inflected forms may not always work as expected. If the following does not give the correct word, try Latin Words or Perseus.

Sāpis, is, m., a river in Cisalpine Gaul and Umbria, between Ravenna and Ariminum, now the Savio, Plin. 3, 15, 20, § 115; Sil. 8, 450; Luc. 2, 406 (al. Isapis).
Hence, Sāpĭnĭus, a, um, adj., of the Sapis, Sapinian: tribus, Liv. 31, 2, 6; 33, 37, 1.