Parsing inflected forms may not always work as expected. If the following does not give the correct word, try Latin Words or Perseus.
Sexītānus (Saxētānus), a, um, adj., of or belonging to Sex (called Σέξ by Ptolem.; Saxetanum in the Itiner.), a town of Hispania Baetica, Sexitan: colias, Plin. 32, 11, 53, § 146; cf. lacertus, Mart. 7, 78, 1.