μονομαχεῖν
From LSJ
καὶ ἐπὶ γῆς εἰρήνη ἐν ἀνθρώποις εὐδοκία → and peace on earth and good will to men, and peace on earth and good will to all
Greek > English (Woodhouse Verbs Reversed)
(see also μονομαχέω): engage in single combat with, engage in single combat, fight a duel, fight man to man