A word from Norse lore referring to an exceptionally vile, despicable person - a person completely without honour. Examples include murderers and oathbreakers. NOTE: "Nithing" is NOT a misspelling of "nothing." It's a totally different word. It's more likely to be used by Heathens (neoPagan followers of the Norse Gods and Goddesses) than by other groups, but it has been seen elsewhere.
I don't know why those nithings expect anyone to fall for their lies anymore, we all know they couldn't tell the truth if their lives depended on it.