From peripsaō (to scrape all around). That which is scraped off, refuse, scum. Paul uses it to describe how the apostles were regarded by the world.
Paul writes: 'We have become the scum of the earth, the garbage of the world' (1 Corinthians 4:13). This is not self-pity but a sober assessment of how the world views faithful servants of Christ. The world's contempt for God's messengers is a badge of authenticity, not shame.