Old Irish ferg

← Proto-Celtic *wergā (inherited)

← Proto-Indo-European *werǵ- (root)

← Proto-Indo-European *wérǵom (inherited)

→ Irish fearg (inherited)

→ Scottish Gaelic fearg (inherited)

→ Manx ferg (inherited)

→ Latin vergivius (mention)

→ Middle Irish ferg (inherited)

→ Old Irish fercaigidir (affix)