Parsing inflected forms may not always work as expected. If the following does not give the correct word, try Latin Words or Perseus.
Sicca, ae, f., a border-town on the east of Numidia, with a temple of Venus, now Kef, Plin. 5, 3, 2, § 22; Sall. J. 56, 3; Val. Max. 2, 6, 15.
Hence, Siccenses, ĭum, m., the inhabitants of Sicca, Sall. J. 56, 4 sq.
Siccenses, ĭum, v. Sicca.