Ἰακός
From LSJ
ἐὰν ἐκπέσῃ τὸ σιδήριον καὶ αὐτὸς πρόσωπον ἐτάραξεν καὶ δυνάμεις δυναμώσει καὶ περισσεία τοῦ ἀνδρείου σοφία (Ecclesiastes 10:10, LXX version) → If the iron axe fails, and the man has furrowed his brow, he will gather his strength, and the redoubling of his manly vigor will be the wise thing.
English (LSJ)
Ἰακή, Ἰακόν, (Ἰάς) Ionic, ἀσωτία Plb.32.11.10; τὸ Ἰακόν the Ionic form, Ath.9.400c; ἡ Ἰ. ἔγκλισις A.D.Pron.98.8. Adv. Ἰακῶς ib.4.21.
Greek (Liddell-Scott)
Ἰακός: -ή, -όν, (Ἰὰς) Ἰωνικός, Πολύβ. παρ’ Ἀθην. 440Β· τὸ Ἰακόν, ὁ Ἰωνικὸς τύπος, Ἀθήν. 400C. ― ’Eπίρρ. -κῶς, Εὐστ. 1064. 4.