Spy

SPY. One who goes into a place for the purpose of ascertaining the best way of doing an injury there.
     2. The term is mostly applied to an enemy who comes into the camp for the purpose of ascertaining its situation in order to make an attack upon it. The punishment for, this crime is death. See Articles of War, 1 Story's Laws U. S. 992; Vattel, Droit des Gens. liv. 3, Sec. 179.

A Law Dictionary, Adapted to the Constitution and Laws of the United States. By John Bouvier. Published 1856.