What’s the difference between contrition and attrition?

Perfect contrition is sorrow for one’s sins based on the selfless motive of love for God and sorrow for having offended him. Attrition is sorrow for one’s sins based on the fear of punishment. For someone in the state of mortal sin (1 John 5:16-17), either kind of sorrow suffices to bring about forgiveness and reconciliation with God in Confession. Perfect contrition necessarily includes the resolution to confess one’s mortal sins to a priest, but it brings God’s forgiveness even before the penitent receives absolution from a priest. Attrition is insufficient to bring about forgiveness apart from the ministry of the priest in Confession.