Espionage or, casually,
spying involves a
spy ring, government and company/firm or individual obtaining information considered
secret or
confidential without the permission of the holder of the information. Espionage is inherently
clandestine, as it is by definition unwelcome and in many cases illegal and punishable by law. Espionage is a subset of "
intelligence" gathering, which includes espionage as well as information gathering from public sources.