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
(1) quārta, æ, f. (s.-ent. pars), le quart : Quint. 8, 5, 19.