Citizen of one country who chose to live his life somewhere else. Usually has extremely compelling reasons for doing so. Occasionally useful as a source. Frequently used only because he speaks the native language of the Case Officer, and is therefore the only person in the country the CO can talk to. Frequently useless because the only thing the expat can say in the local lingo is “Bring me another gin and tonic boy.” This is the guy people are referring to when they say they have a source “on the ground.” Highest and best use: picking up the gossip from people at the Hilton poolside.