Ἓν οἶδα, ὅτι οὐδὲν οἶδα → I know only one thing, that I know nothing | all I know is that I know nothing.
P. and V. δυστυχής, ἀτυχής (rare V.), Ar. and V. δύσποτμος; see unfortunate.
harmful: P. and V. ἀσύμφορος; see harmful.