Pronunciation: /fɪfθ ˈkɒləm/
noun a clandestine or subversive group that works within a larger organization or country to undermine its operations or goals
A1 I heard about a fifth column in the city, but I'm not sure what it means.
A2 The spy was suspected of being part of a fifth column working against the government.
B1 During the war, there were rumors of a fifth column operating within the country.
B2 The military had to take action to root out the fifth column before they could cause any more damage.
C1 The existence of a fifth column posed a serious threat to national security.
C2 Intelligence agencies worked tirelessly to uncover the members of the fifth column and dismantle their operations.
formal The government was concerned about the presence of a fifth column within the country.
informal They suspected that there was a fifth column working against them from within.
slang The authorities were on high alert for any signs of a fifth column activity.
figurative In times of crisis, it's important to be vigilant for any potential fifth column threats.
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