τολμηρόν
From LSJ
εἰ ἀποκρυπτόντων τῶν Μήδων τὸν ἥλιον ὑπὸ σκιῇ ἔσοιτο πρὸς αὐτοὺς ἡ μάχη καὶ οὐκ ἐν ἡλίῳ → if the Medes hid the sun, the battle would be to them in the shade and not in the sun
Russian (Dvoretsky)
τολμηρόν: τό
1) дерзание, смелость Thuc.;
2) смелый поступок, подвиг Arst.