Foolishness is the lack or failure of wisdom and of making proper careful choices. In this sense, it differs from stupidity, which is the lack of intelligence. An act of foolishness is called folly. Foolish talk is called stultiloquence.
Foolishness and wisdom are contrasted in Paul's letter to the Corinthians. He condemns intellectual arrogance and advocates a humble attitude of foolishness in which it is then possible to learn. Plato likewise said, "He is the wisest man who knows himself to be ill-equipped for the study of wisdom", but Paul makes a distinction between wisdom and the reason of the Greeks.