Πρωταγόρειος
From LSJ
πολλὰ μεταξὺ πέλει κύλικος καὶ χείλεος ἄκρου → there is many a slip twixt cup and lip, there's many a slip twixt cup and lip, there's many a slip 'twixt cup and lip, there's many a slip twixt the cup and the lip, there's many a slip 'twixt the cup and the lip
English (LSJ)
α, ον,
A of Protagoras, μέτρον Pl.Tht.162c; μῦθος ib. 164d.
Greek (Liddell-Scott)
Πρωτᾰγόρειος: -α, -ον, ὁ εἰς τὸν Πρωταγόραν ἀνήκων, μῦθος Πλάτ. Θεαίτ. 126C, 164D.
Russian (Dvoretsky)
Πρωτᾰγόρειος: протагоров(ский).