Fenian (plural Fenians)
- (UK, Ireland) An Irish nationalist or republican.
- (historical) A member of the Fenian Brotherhood or the Irish Republican Brotherhood, Irish republican organizations active in the nineteenth and early twentieth centuries.
- (derogatory , Scotland and Northern Ireland) A Catholic, especially one of Irish ethnicity or descent.
- (derogatory , Scotland and Northern Ireland) A supporter of Scottish association football club Celtic F.C.