Which term refers to the unlawful disclosure of classified information to foreign entities?

The term that specifically refers to the unlawful disclosure of classified information to foreign entities is espionage. This activity involves gathering, transmitting, or losing information related to national defense or foreign relations, valuable to the adversary. Espionage can take many forms, including espionage conducted by individuals or governments, and is often associated with spying or clandestine activities aimed at obtaining sensitive information for strategic advantage.

Counter-intelligence, while relevant, focuses on efforts to prevent espionage and sabotage rather than the act of unlawfully disclosing information itself. Subversion involves undermining the power and authority of an established system or institution, which does not specifically pertain to the disclosure of classified information. Insider threats encompass a broader category of risk by involving individuals within an organization misusing their access to systems and information; however, it does not exclusively indicate the act of disclosing information to foreign entities. Thus, espionage is the precise term for such unlawful disclosures.