ἀντιχρηματίζομαι
From LSJ
χαῖρ', ὦ μέγ' ἀχρειόγελως ὅμιλε, ταῖς ἐπίβδαις, τῆς ἡμετέρας σοφίας κριτὴς ἄριστε πάντων → all hail, throng that laughs untimely on the day after the festival, best of all judges of our poetic skill
English (LSJ)
A 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.).