Parsing inflected forms may not always work as expected. If the following does not give the correct word, try Latin Words or Perseus.
1. vibo, ōnis, m., the flower of the herb called Britannica, Plin. 25, 3, 6, § 21.
2. Vibo or Vibon, ōnis, f., a town in the territory of the Bruttii, now Monteleone, Mel. 2, 4, 9; Plin. 3, 5, 10, § 73; Cic. Att. 16, 6, 1; Mart. Cap. 6, § 645.
Hence, Vibōnensis, e, adj., of or belonging to Vibo: ager, Liv. 21, 51, 4 sqq.; Cic. Att. 16, 6, 1.