The “nude figure” is Oedipus. But the Greek inscription is much more relevant here ―on the ex-libris of the father of psychoanalysis― than the fact that a Oedipus is naked. The Greek inscription reads: “oV ta klein ainigmata hdei, kai kratistoV hn anhr”. It’s taken from Sophocles’ Oedipus King (vv. 1525) and it means:

The one who understood that celebrated riddle. He was the most powerful of men.