sin, noun. 1. An action which deserves universal condemnation, and which promotes evil rather than good in the world. Sin exists among politicians and other secular leaders who set policies with which we disagree; however, sin does not exist among religious liberals. The following sentence is a proper use of the word — When Governor Sanford cheated on his wife, it was a sin. However, when the speaker is a religious liberal, the proper construction would be as follows — When I cheated on my spouse, we went into couples therapy together so we could resolve our issues. (N.B.: For those religious liberals who agreed with Governor Sanford’s policies, his action was not a sin, but was instead evidence that he needed therapy.)