Sleeper agent

Spy in place with no immediate mission

A sleeper agent is a spy or operative who is placed in a target country or organization, not to undertake an immediate mission, but instead to act as a potential asset on short notice if activated. Even if not activated, the "sleeper agent" is still an asset and can still play an active role in sedition, espionage, or possibly treason by virtue of agreeing to act if activated. A team of sleeper agents may be referred to as a sleeper cell. A sleeper cell or agent may possibly be working with others in a clandestine cell system.

This keyword could refer to multiple things. Here are some suggestions: