spy / spī/ • n. (pl. spies) a person who secretly collects and reports information on the activities, movements, and plans of an enemy or competitor. ∎ a person who keeps watch on others secretly: [as adj.] a spy camera. • v. (spies, spied, spy·ing) [intr.] work for a government or other organization by secretly collecting information about enemies or competitors: he agreed to spy for the West. ∎ (spy on) observe (someone) furtively: the couple were spied on by reporters. ∎ [tr.] discern or make out, esp. by careful observation: he could spy a figure in the distance. ∎ [tr.] (spy something out) collect information about something to use in deciding how to act: he would go and spy out the land.