Espionage, spying, or intelligence gathering, as a subfield of the intelligence field, is the act of obtaining secret, confidential, or in some way valuable information.

Phrasal verb spy on someone/something (Definition of spying from the Cambridge Advanced Learner's Dictionary & Thesaurus © Cambridge University Press)

Espionage is defined as the act of spying or using spies, agents, assets, and intelligence officers, as well as technology, to collect secret information, usually through illegal means.

: a person employed by one nation to secretly convey classified information of strategic importance to another nation also : a person who conveys the trade secrets of one company to …

1. To engage in espionage. 2. To investigate or observe something, especially in secret: spying into the neighbor's activities.

Nov 7, 2025 · In 1962 the Soviet Union began to secretly install missiles in Cuba to launch attacks on U.S. cities. The confrontation that followed, known as the Cuban missile crisis, brought the …

Spying is the act or process of finding out secret information for a country or organization about other countries or organizations. ...a ten-year sentence for spying.