Parsing inflected forms may not always work as expected. If the following does not give the correct word, try Latin Words or Perseus.
Centobrīga, ae, f., a town of the Celtiberi in Spain, Val. Max. 5, 1, 5.
Hence, Centobrīgenses, ĭum, m., the inhabitants of Centobriga, Val. Max. 5, 1, 5.