Parsing inflected forms may not always work as expected. If the following does not give the correct word, try Latin Words or Perseus.
Antandrŏs (-us), i, f., = Ἄντανδρος, a maritime town in Mysia, now Antandro (acc. to Thuc. 8, 108, an Æolic colony), Plin. 5, 30, 32, § 123; cf. Mann. Asia Min. 3, 418.
Hence, Antandrius, a, um, adj., of Antandros, Cic. ad Q. Fr. 1, 2, 2.