ἄκλονος
From LSJ
μοῦνοι Ἑλλήνων δὴ μουνομαχήσαντες τῷ Πέρσῃ → alone of all Greeks we met the Persian singlehandedly, alone of all Greeks having fought singlehanded with the Persians
English (LSJ)
ον, of the pulse,
A steady, regular, Gal.9.347; of a limb, free from jars, 17(1).513; of a rider, with a firm seat, Palaeph.52.
Greek (Liddell-Scott)
ἄκλονος: -ον, ὁ μὴ κλονιζόμενος, Γαλην. τόμ. 9. 205.