1. the practice of spying or using spies to obtain secret information, especially for military or political purposes

Examples

• The diplomat was expelled for engaging in espionage.
• Industrial espionage threatens company trade secrets.
• The novel features a thrilling tale of international espionage.
• Government agencies work to prevent foreign espionage.
• He was convicted of espionage and sentenced to prison.
• The Cold War era was marked by extensive espionage activities.