ἐπιγυμνάζω
From LSJ
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
English (LSJ)
A exercise excessively, Philostr.Gym.51; exercise again, ib.53:—Pass, take exercise at or in, τοῖσι γυμνασίοισι Hp.Insomn.88: abs., dub. in Ph.1.467.
German (Pape)
[Seite 934] noch dazu, dabei üben, Philo; in der Uebung zusetzen, Hippocr.