'Foolish' in the Bible

So I decided to discern the benefit of wisdom and knowledge over foolish behavior and ideas; however, I concluded that even this endeavor is like trying to chase the wind!

Next, I decided to consider wisdom, as well as foolish behavior and ideas. For what more can the king's successor do than what the king has already done?

A poor but wise youth is better than an old and foolish king who no longer knows how to receive advice.

At the beginning his words are foolish and at the end his talk is wicked madness,