ἀρθρεμβολέομαι

From LSJ

κέρκος τῇ ἀλώπεκι μαρτυρεῖ → you can tell a fox by its tail, small traits give the clue to the character of a person

Source

Spanish (DGE)

ensamblarse una pieza de una máquina ἡ ... θερμαστρὶς ... εἰς ἣν ἀρθρεμβολεῖται ὁ λεγόμενος ὁδηγός Ath.Mech.34.6.