I'm going to guess people are a lot more familiar with Catholicism than Heathenry, so why not educate about every religion and not just one?
Today's word: oathbreaker
An oathbreaker is someone who swears allegiance to a family, deity, or other symbolic entity, and then violates the terms of that allegiance. Or, it's someone who pledges to do something, and then knowingly fails to do so.
Examples would be saying prayers or going through ceremonies to declare oneself a devotee of a religion, then repeatedly breaking the tenets of that religion, such as being hateful, spiteful, or catty after joining a faith which puts stress on loving one's fellow man. Or, pledging to make some sort of personal sacrifice or habit change, giving something up for a month, or ignoring something that bothers you, then turning around and continuing the habit in secret, or continuing to interact with whatever was supposed to be ignored.
In Heathenry, being an oathbreaker is the foulest thing a person can be. It surpasses murder and stealing. An oathbreaker is someone completely undeserving of respect or even common courtesy, and they, along with liars, are considered the only people who will not find peace in the afterlife. A murder or theft can be justified, while oathbreaking is a sign of a much deeper flaw within a person's very nature.
Breaking an oath is one of the most difficult crimes to recompense. There is no simple monetary value or act of kindness that will alleviate the chasm of mistrust it creates, not just with the people or thing to whom the oath was made, but to all the other people who witness the act.