spy

American  

[spahy] / spaɪ /

noun

spies plural

1. a person employed by a government to obtain secret information or intelligence about another, usually hostile, country, especially 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, especially one who is employed for this purpose by a competitor.

   an industrial spy.

4. the act of spying.

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verb (used without object)

spied, spying

1. to observe secretively or furtively with hostile intent (often followed by on orupon ).

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.

verb (used with object)

spied, spying

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 followed byout ).

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.

spy British  

/ spaɪ /

noun

1. a person employed by a state or institution to obtain secret information from rival countries, organizations, companies, etc

2. a person who keeps secret watch on others

3. obsolete a close view

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verb

1. to keep a secret or furtive watch (on)

2. (intr) to engage in espionage

3. (tr) to catch sight of; descry

Other Word Forms

• outspy
  verb (used with object)
• spyship
  noun
• superspy
  noun
• unspied
  adjective
• unspying
  adjective

Etymology

Origin of spy

First recorded in 1200–50; (for the verb) Middle English spien, shortened from espien, espyen “to espy” ( see espy); (for the noun) Middle English, shortened from espy “a spy,” from Old French espie

Explanation

To spy is to secretly watch someone. It’s not recommended unless you’re actually a spy, a person who is hired by a government or organization to keep tabs on enemies. You might imagine a spy working for the CIA or the KGB, but there are also military spies who infiltrate their opponents' armies to get information, commit sabotage, or steal technology. Private businesses sometimes employ spies as well, to collect information about competitors. As a verb, to spy is to do what a spy does—or simply to see something: "I spy brownies on the kitchen counter!"

Example Sentences

The UK is at a "moment of consequence" as Russia is "relentlessly targeting" critical infrastructure, the UK's largest spy agency will warn.

From BBC • May 26, 2026

After 9/11, the government punished ordinary Muslim Americans who refused its overtures to spy, at great personal cost, for it.

From Slate • May 26, 2026

I imagined he was in the CIA, and often away on spy missions.

From The Wall Street Journal • May 26, 2026

A former Democrat, Gabbard was a surprising choice to lead the giant US spy apparatus given her previous history of questioning intelligence and opposition to America's foreign military interventions.

From Barron's • May 22, 2026

Knowing his love of spy novels, they figured he was joking about the Soviets having an actual fission device hidden in the Soviet embassy in Washington.

From "Fallout: Spies, Superbombs, and the Ultimate Cold War Showdown" by Steve Sheinkin

Related Words

• agent
• detective
• informer
• investigator
• mole
• operative
• secret agent
• secret service
• undercover agent