Ἓν οἶδα, ὅτι οὐδὲν οἶδα → I know only one thing, that I know nothing | all I know is that I know nothing.
ἀγνωστί, ἀγνώστως, ἀποκρύφως, ἀπορρήτως, ἀσυμφανῶς, ἀφανῶς, δι' ἀπορρήτων, ἐγκεκαλυμμένως, ἐν ἀποκρύφῳ, ἐν ἀπορρήτῳ, ἐν κρυφῇ, κρύβδα, κρύβδην, κρυφᾷ, κρύφα, κρυφαίως, κρυφῇ, κρυφῆ, κρυφηδόν, κρυφίως, λάθρα, λάθρᾳ, λαθραίως, λανθανόντως, σιγῇ, σκότιον