The meaning changed through time. From earliest to modern defs:
1. a 19th & 20th century Irish organization dedictated to an independant Ireland via armed revolution.
2. a supporter of anything Irish
3. [derogatory] an Irish Catholic
► uses
Uses:
I remember the famine in '46. Do you know that the orange lodges agitated for repeal of the union twenty years before O'Connell did or before the prelates of your communion denounced him as a demagogue? You fenians forget some things.