Definition of "undercover agent" [undercover agent]

• (military) a secret agent hired by a state to obtain information about its enemies or by a business to obtain industrial secrets from competitors (noun)

WordNet. Princeton University. 2010.

• "His name is Mike Frye, and Mike was sent over there as a sort of undercover agent who looked like a student and so forth, and they found out who he was and they named "Agent of the"
• "He took tea with the Appelhardts; his undercover agent made his first report; Lyle Compton presented his program on Scotland at the hotel; and Yum Yum found something among the sofa cushions."