Lewis & Short

1. Vĭrĭāthus or Vĭrĭātus, i, m., a celebrated leader of the Lusitanians in the war against the Romans, Liv. Epit. 52; 54; Vell. 2, 1, 3; 2, 90, 3; Flor. 2, 17 fin.; Cic. Off. 2, 11, 40; Val. Max. 6, 4, 2; Sil. 4, 354; 10, 219.
Vĭrĭāthīnus or Vĭrĭātīnus, a, um, adj., of or pertaining to Viriathus: bellum, Suet. Galb. 3.