Definition of: spy

(spī) noun plural spies
1. One who enters an enemy's military lines covertly to get information; a secret agent.
2. One who watches others secretly: often used contemptuously.
3. A peep; glance; hence, an eye.
4. The act of watching secretly.
—v. spied, spy·ing v.i.
1. To keep watch closely or secretly; act as a spy.
2. To make careful examination; pry: with into.
—v.t.
3. To observe stealthily and with hostile intent: usually with out.
4. To catch sight of; see; espy.
5. To discover by careful or secret investigation: with out.
6. To examine or scrutinize carefully. [<OF espie <espier espy <Gmc.] Synonyms (noun): emissary, scout. The scout and the spy are both employed to obtain information of the numbers, movements, etc., of an enemy. The scout lurks on the outskirts of the hostile army with such concealment as the case admits of, but without disguise; a spy enters in disguise within the enemy's lines. A scout, if captured, has the rights of a prisoner of war; a spy is held to have forfeited all rights, and is liable, in case of capture, to capital punishment. Soldiers not in disguise or military aviators are not considered spies, even while passing through or over hostile territory. An emissary is rather political than military, sent to influence opponents secretly rather than to bring information concerning them.