Lewis & Short

Grājŭgĕna, ae, m. [Graius-gigno; cf. Graecigena], a Grecian by birth, a Greek (poet.): Grajugena, Pac. ap. Cic. N. D. 2, 36, 91: equus Grajugenarum, Lucr. 1, 477: Grajugenūmque domos suspectaque linquimus arva, Verg. A. 3, 550.
Adj.: Grajugenae reges, Stat. Th. 6, 215.