The Greek noun aphrosyne comes from the negative particle a- and phronesis (understanding, wisdom), meaning the absence of wisdom — foolishness or senselessness. It appears four times in the New Testament (Mark 7:22; 2 Corinthians 11:1, 17, 21), where Paul repeatedly and ironically calls his own "boasting" a form of aphrosyne — foolishness — while subverting the Corinthians' worldly wisdom criteria.
Paul's ironic use of aphrosyne in 2 Corinthians 11 is a masterpiece of rhetorical reversal. He calls his own self-defense "foolishness" to expose the Corinthians' foolishness in demanding worldly credentials from apostles. True apostolic authority is demonstrated in suffering, weakness, and service — not in impressive letters or eloquent speech. Jesus placed aphrosyne in the heart's inventory of sin (Mark 7:22), showing that foolishness is not just intellectual but moral — the refusal to fear God and live wisely before Him.