noun
counterintelligence; counterespionage
Refers to activities and measures taken to prevent enemy intelligence operations, such as spying or sabotage.
防諜活動は国家の安全にとって不可欠だ。
Counterintelligence activities are essential for national security.
彼は防諜の専門家として知られている。
He is known as an expert in counterespionage.