Espionage was the practice of obtaining information or intelligence on an individual, group or political entity, often of a military nature. A person who engaged in the act of espionage was known as a spy. Alec Palmer specialised in, among other things, espionage behind enemy lines. (TV: Hide)
At LINDA, Victor Kennedy's classes covered basic surveillance and espionage. (TV: Love & Monsters)
On the Inferno Earth espionage was a crime punishable by death. (TV: Inferno)