n. The act or process of learning secret information through clandestine means.
the GNU version of the Collaborative International Dictionary of English
n. The practice or employment of spies; the practice of watching the words and conduct of others, to make discoveries, as spies or secret emissaries; secret watching.
The Century Dictionary and Cyclopedia
n. The practice of spying; secret observation of the acts or utterances of another by a spy or emissary; offensive surveillance.
WordNet 3.0 Copyright 2006 by Princeton University. All rights reserved.
n. the systematic use of spies to get military or political secrets
Word Usage
"Peruvian-Chilean relations have been generally good of late and Peruvian officials including Defense Minister Luis Alberto Otarola avoided the word "espionage" when questioned by reporters about the arrests of Serain and Pizarro."