What does Proverbs 1:20 mean?

Verse 20 paints a picture of wisdom, personified as a woman, crying out in the market place. The reason for staging this image in the marketplace is visibility. The market is a crowded, public area, one where everyone in the community needs to go. In other words, Solomon is suggesting that wisdom is accessible to anyone and everyone who actually wants it. And, because she "cries aloud" and "raises her voice" in a public place, even those who aren't specifically seeking her are going to encounter her, at least by accident. Wisdom does not hide itself. It is clear and present. Even those who don't seek wisdom will stumble into it, at times. The only way to completely avoid wisdom is to purposefully ignore it.

There is a contrast here between wisdom and the sins Solomon described in verses 11–14. Sin is enticing, in a get-rich-quick sense. Wisdom is available, and accessible to anyone, but it also requires work.