Counterintelligence refers to activities aimed at protecting a nation's intelligence operations from espionage, sabotage, or other intelligence threats. It involves identifying and neutralizing foreign spies or hostile entities that seek to gather sensitive information. This can include monitoring communications, conducting investigations, and employing various security measures. The goal of counterintelligence is to safeguard national security and ensure that critical information remains confidential. Agencies like the FBI and CIA in the United States play significant roles in these efforts, working to prevent unauthorized access to classified data and to protect the integrity of intelligence operations.