διαπεπειρᾶσθαι
From LSJ
Ἓν οἶδα, ὅτι οὐδὲν οἶδα → I know only one thing, that I know nothing | all I know is that I know nothing.
Greek > English (Woodhouse Verbs Reversed)
(see also διαπειράομαι): to have had a foretaste of, to have had a taste of, to have had experience of