Ergi: The History

Ergi and argr are two Old Norse terms of insult, denoting effeminacy or other unmanly behavior. Argr is "unmanly" and ergi is "unmanliness".

Origin
To accuse another man of being argr was called scolding, and thus a legal reason to challenge the accuser in holmgang. If holmgang was refused by the accused, he could be outlawed, as this refusal proved that the accuser was right and the accused was unmanly and cowardly. If the accused fought successfully in holmgang and had thus proven that he was not unmanly, the scolding was considered an unjustified, severe defamation, and the accuser had to pay the offended party full compensation.

Reference: Wikipedia