λῃστρικῶς

From LSJ

εἷς οἰωνὸς ἄριστος, ἀμύνεσθαι περὶ πάτρης → the best goal is defending your country

Source

French (Bailly abrégé)

adv.
comme des brigands.
Étymologie: λῃστρικός.

Russian (Dvoretsky)

λῃστρικῶς: по-разбойничьи Plut.