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

With SPY around $714.91, investors could hedge the market by buying the May $706 put that expires on May 1, and sell the May $690 put with the same expiration.

From Barron's • Apr. 28, 2026

So in return for protecting 90% of investors’ capital on a quarterly basis, the fund’s annual return turned out to be 77% that of SPY.

From MarketWatch • Apr. 28, 2026

Should SPY rally, however, the money spent on the hedge would be lost.

From Barron's • Apr. 28, 2026

So here are returns and expense ratios for four defined-outcome ETFs for one year and three years through April 27, with SPY at the bottom for reference.

From MarketWatch • Apr. 28, 2026

Sir, Titus   Cassius yawned while thou didst sing. 4TH SPY.

From Nero by Phillips, Stephen

Related Words

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