—n. 1. a person employed by a government to obtain secret information or intelligence about another, usually hostile, country, esp. with reference to military or naval affairs.
2. a person who keeps close and secret watch on the actions and words of another or others.
3. a person who seeks to obtain confidential information about the activities, plans, methods, etc., of an organization or person, esp. one who is employed for this purpose by a competitor: an industrial spy. 4. the act of spying.
—v.i. 1. to observe secretively or furtively with hostile intent (often fol. by on or upon).
2. to act as a spy; engage in espionage.
3. to be on the lookout; keep watch.
4. to search for or examine something closely or carefully.
—v.t. 1. to catch sight of suddenly; espy; descry: to spy a rare bird overhead. 2. to discover or find out by observation or scrutiny (often fol. by out).
3. to observe (a person, place, enemy, etc.) secretively or furtively with hostile intent.
4. to inspect or examine or to search or look for closely or carefully.