Ἀχαιός
From LSJ
ὁ δὲ πείσεται εἰς ἀγαθόν περ → he will obey you to his profit, he will obey you for his own good end
English (LSJ)
ά, όν,
A Achaean, Hom., etc.: hence as Subst., 1 Ἀχαιοί, οἱ, the Achaeans, in Hom. for the Greeks generally, Il.2.235, etc. 2 Ἀχαΐα, ἡ, Achaia in Peloponnese, Th., etc.; under the Romans, the prouince of Greece.
Greek (Liddell-Scott)
Ἀχαιός: -ά, -όν, ὁ ἐξ Ἀχαίας, Λατ. Achivus, Ὅμ., κλ.· ἐντεῦθεν ὡς οὐσιαστ., 1) Ἀχαιοί, οἱ παρ’ Ὁμ. ἀντὶ τοῦ Ἕλληνες ἐν γένει, κυρίως δὲ Σπαρτιᾶται καὶ Ἀργεῖοι, Παυσ. 7. 1. 2) Ἀχαΐα, ἡ, ἐν Πελοποννήσῳ, Θουκ. κλ., ἀλλλ’ ὑπὸ τοὺς Ρωμαίους περιελάμβανεν ἅπασαν τὴν Ἑλλάδα, πλὴν τῆς Θεσσαλίας.