αὐτόγνωτος
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 self-determined, self-willed, ὀργή S.Ant.875:—alsoαὐτό-γνωστος, ον, knowable in itself, Simp.in Ph.1250.14, Dam.Pr.80.