An enemy group within and threatening a larger entity is called a '(What?) Column'?
Fifth column Fifth column A fifth column is any group of people who undermine a larger group from within, usually in favour of an enemy group or nation. 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 organised 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. During the Siege of Madrid in the Spanish Civil War, Nationalist general Emilio Mola told a journalist
Enemy Enemy An enemy or a foe is an individual or a group that is verified as forcefully adverse or threatening. The concept of an enemy has been observed to be "basic for both individuals and communities". The term "enemy" serves the social function of designating a particular entity as a threat, thereby invoking an intense emotional response to that entity. The state of being or having an enemy is enmity, foehood or foeship. Enemy comes from the 9th century Latin word "inimi", derived from Latin for "bad friend" (). "Enemy" is a strong word, and "emotions associated with the enemy