μεσίτης
From LSJ
οἱ Κυρηναϊκοὶ δόξαις ἐχρῶντο τοιαύταις: δύο πάθη ὑφίσταντο, πόνον καὶ ἡδονήν, τὴν μὲν λείαν κίνησιν, τὴν ἡδονήν, τὸν δὲ πόνον τραχεῖαν κίνησιν → the Cyrenaics admitted two sensations, pain and pleasure, the one consisting in a smooth motion, pleasure, the other a rough motion, pain
English (LSJ)
ου, ὁ,
A mediator, umpire, arbitrator, PLille28.11 (iii B. C.), Plb.28.17.8 (pl.), Ep.Gal.3.19, etc.; τῶν ὁμολογιῶν D.S.4.54; θεοῦ καὶ ἀνθρώπων 1 Ep.Ti.2.5; stakeholder, PStrassb.1.41.14 (iii A. D.). 2 fem. μεσῖτις, ιδος, fili/as mesi=tin tra/pezan paraqe/menoi Luc.Am.27; φιλίας μ. ἡδονή ib.54. II in a middle position, of a limb, Gal.18(2).861.
