Parsing inflected forms may not always work as expected. If the following does not give the correct word, try Latin Words or Perseus.
Lacobrĭga, ae, f., a town of Lusitania, Mel. 1, 3, 6.
Hence, Lacobrĭgenses, ium, m., the inhabitants of Lacobriga, Plin. 3, 3, 4, § 26.