ἀντιχρηματίζομαι
From LSJ
τούτων γάρ ὄνομα μόνον κοινόν, ὁ δέ κατά τοὔνομα λόγος τῆς οὐσίας ἕτερος → though they have a common name, the definition corresponding with the name differs for each (Aristotle, Categoriae 1a3-4)
English (LSJ)
transact business instead of another, PFlor.382.59 (iii A.D.).
Spanish (DGE)
actuar en nombre de otro, representar, PMich.529ue.49 (III d.C.), cf. PFlor.382.59 (III d.C.).