A fifth column is a group of people who undermine a larger group, such as a nation or a besieged city, from within. The activities of a fifth column can be overt or clandestine. Forces gathered in secret can mobilize openly to assist an external attack. This term is also extended to organized actions by military personnel. Clandestine fifth column activities can involve acts of sabotage, disinformation, or espionage executed within defense lines by secret sympathizers with an external force.
An example, the major example is the Subversion being carried out by Zionist crazies in Western Civilization now. It is the reason why we have Zionist Occupation Governments [ ZOGs ] throughout the English speaking world as well as Europe.