Parsing inflected forms may not always work as expected. If the following does not give the correct word, try Latin Words or Perseus.
Illiberi (Ili-, -erri), n. indecl. (f. acc. -im, Liv. 21, 24, 3), a city of Hispania Bœtica, between the Bœtis and the coast, now Granada, Mel. 2, 6, 8; Plin. 3, 1, 3, § 10; Liv. 21, 24, 1.