ἀκρύβδηλος

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

Source

Spanish (DGE)

-ον
prob. forma acuñada como etim. de ἀκίβδηλος no escondido, franco, EM α 660.