Spies have played a significant role in global politics and have been referred to by various names throughout history. "Agent of espionage" refers to an individual or entity that collects sensitive information from a group or nation on behalf of another group or nation. Synonyms for this term include espionage agent, intelligence operative, secret agent, spy, cloak-and-dagger man, undercover agent, and spy master. Other related terms include mole, double agent, and sleeper agent. These terms often have shades of meaning, with some referring to a specific type or level of espionage, while others are more general in nature. Regardless of the term used, the role of agents of espionage has remained an important aspect of international relations.