Lewis & Short

Ăchīvus, a, um (gen. plur. Achivom, Verg. A. 11, 266), adj. [fr. Achaeus, with the Digamma, Achaefos, Achifus, Achivus], Achaean, Grecian (v. Achaia): tellus, Ov. Pont. 1, 4, 33: castra, id. H. 1, 21.
Hence, Ăchīvi, the Greeks, Cic. Div. 1, 14: quidquid delirant reges plectuntur Achivi, whatever wrongs the (Grecian) kings are guilty of (before Troy) their subjects must suffer for; but it soon became a general proverb: whatever errors the great commit, the people must atone for, Hor. Ep. 1, 2, 14.