A Roman Catholic (and derivatives thereof, i.e. Lutheran) ritual in which a person receives a formal remission of sin imparted by a priest as part of the sacrament of penance.
To sin, in essence, is to miss the mark, and if any Karma is involved, it is up to the individual to work out his or her own karma. No other individual, priest or otherwise, can provide absolution. Only the natural law of cause and effect is at work at all times. If absolution can be freely given, it would make a mockery of the standing between sinners and saints.