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
ἄοκνος, ἀπρόσκεπτος, ἀπρόσκοπος, ἀπροόρατος, ἀπροσκόπητος