Origin: See Spy, and cf. Espy.
2. A person sent secretly into an enemy's camp, territory, or fortifications, to inspect his works, ascertain his strength, movements, or designs, and to communicate such intelligence to the proper officer. Spy money, money paid to a spy; the reward for private or secret intelligence regarding the enemy. Spy wednesday, the Wednesday immediately preceding the festival of Easter; so called in allusion to the betrayal of christ by judas Iscariot.