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A clandestine subversive organization working within a country to further an invading enemy's military and political aims.
[First applied in 1936 to rebel sympathizers inside Madrid when four columns of rebel troops were attacking that city.]
fifth col′um·nism (kŏl′əm-nĭz′əm) n.
fifth columnist n.
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|Noun||1.||fifth columnist - a member of a clandestine subversive organization who tries to help a potential invader|
fifth column, Trojan horse - a subversive group that supports the enemy and engages in espionage or sabotage; an enemy in your midst