From Longman Dictionary of Contemporary Englishcounter-espionageˌcounter-ˈespionage noun [uncountable] the process of trying to stop someone spying on your country
Examples from the Corpus
counter-espionage• Without ciphers and diplomatic bags, espionage and counter-espionage actions were likely to be circumscribed.• But the republican counter-espionage was highly organized, and early in 1814 he was arrested, tried and condemned to death.• They're political - a small counter-espionage unit. 