unconquerable
From LSJ
English > Greek (Woodhouse)
adj.
P. and V. δύσμαχος, ἀνίκητος, Ar. and P. ἄμαχος (Plat.), P. δυσπολέμητος, V. δυσπάλαιστος, ἀπρόσμαχος, ἀδήριτος.
Impossible to deal with: P. and V. ἄπορος, ἀμήχανος (rare P.).
Obstinate: see obstinate.