ἔγνω δὲ φώρ τε φῶρα καὶ λύκος λύκον → the thief knows the thief and the wolf knows the wolf, and thief knows thief and wolf his fellow wolf, set a thief to catch a thief
ἰσχαίνω (Α)εμποδίζω.[ΕΤΥΜΟΛ. Μεταπλασμένος τ. ενεστώτα του ρ. ἴσχω].