ἰθεῖαν
From LSJ
κακοὶ μάρτυρες ἀνθρώποισιν ὀφθαλμοὶ καὶ ὦτα βαρβάρους ψυχὰς ἐχόντων → eyes and ears are poor witnesses for men if their souls do not understand the language (Heraclitus Phil.: Fr. B 107; Testimonia: Fragment 16, line 6)
French (Bailly abrégé)
adv.
v. ἰθύς.
Russian (Dvoretsky)
ἰθεῖαν: adv. (sc. ὀδόν) по прямому направлению, прямо (ἰ. ἐς τὸν κόλπον Her.).