ἀνερμήνευτος
From LSJ
ἀμήχανον δὲ παντὸς ἀνδρὸς ἐκμαθεῖν ψυχήν τε καὶ φρόνημα καὶ γνώμην, πρὶν ἂν ἀρχαῖς τε καὶ νόμοισιν ἐντριβὴς φανῇ → hard it is to learn the mind of any mortal or the heart, 'till he be tried in chief authority | it is impossible to know fully any man's character, will, or judgment, until he has been proved by the test of rule and law-giving
English (LSJ)
ον,
A with none to interpret, E.Hyps.Fr.1 iv18. II inexplicable, indescribable, τῷ πέλας S.E.M.7.65; ὀδύνη Aristaenet. 2.5.