Lewis & Short

Parsing inflected forms may not always work as expected. If the following does not give the correct word, try Latin Words or Perseus.

Agrĭgentum, i, n., one of the largest and richest cities on the south coast of Sicily, near Cape Pachynum, acc. to the Greek (Ἀκράγας) sometimes called Acragas or Agragas, now Girgenti.
Here was the temple of Juno Lucina, so renowned in antiquity, whose ruins are still to be seen: oppidum Acragas, quod Agrigentum nostri dixere, Plin. 3, 8, 14, § 89: alia judicia Lilybaei, alia Agrigenti restituta sunt, Cic. Verr. 2, 2, 26.
Hence, Agrĭgentīnus, a, um, adj., of or from Agrigentum: sal, Plin. 31, 7, 41, § 85.
Subst.: Agrĭgentīni, ōrum, m., the inhabitants of Agrigentum, Cic. Verr. 2, 2, 50.