A walk-in agent is an individual who voluntarily offers to conduct espionage. Specifically, a "walk-in" is an agent or a mole of a government who literally walks into an embassy or intelligence agency without prior contact or recruitment.
Famous quotes containing the words walk-in and/or agent:
“With four walk-in closets to walk in,
Three bushes, two shrubs, and one tree,
The suburbs are good for the children,
But no place for grown-ups to be.”
—Judith Viorst (b. 1935)
“Only a fully trained Jedi knight with the Force as his ally will conquer Vader and his emperor. If you end your training now—if you choose the quick and easy path, as Vader did—you will become an agent of evil.”
—Leigh Brackett (1915–1978)