Cosin

Cosin: verb. When two or more people partake in the same sin. All cosins are sins, but not all sins are cosins. For example, as far as numerous religious texts are concerned, incest is a cosin, whereas murder can only be a cosin when more people do the killing. However, if an individual is involved in killing someone who is committing suicide, then it is not a cosin, as one of the people concerned committed the sin of suicide while the other committed the sin of murder. A person who cosins is called a cosinner - a label which remains with the person until his or her death in the same way that an ex dies an ex even if his or her relationship was succeeded by many others.