molly maguire

from The Century Dictionary.

• noun A member of a lawless secret association in Ireland, organized with the object of defeating and terrorizing agents and process-servers, and others engaged in the business of evicting tenants.
• noun A member of a secret organization in the mining regions of Pennsylvania, notorious for the commission of various crimes, including murderous attacks upon the owners, officers, or agents of mines, until their suppression by the execution of several of their leaders, about 1877.