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!"

Definitions of spy
  1. noun
    (military) a secret agent hired by a state to obtain information about its enemies or by a business to obtain industrial secrets from competitors
    synonyms: undercover agent
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    Margarete Gertrud Zelle
    Dutch dancer who was executed by the French as a German spy in World War I (1876-1917)
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    counterspy, mole
    a spy who works against enemy espionage
    double agent
    a spy who works for two mutually antagonistic countries
    espionage agent
    someone employed to spy on another country or business competitor
    foreign agent
    a spy for a foreign country
    someone who takes up a position surreptitiously for the purpose of espionage
    a spy or saboteur or terrorist planted in an enemy country who lives there as a law-abiding citizen until activated by a prearranged signal
    type of:
    intelligence agent, intelligence officer, operative, secret agent
    a person secretly employed in espionage for a government
  2. noun
    a secret watcher; someone who secretly watches other people
    “my spies tell me that you had a good time last night”
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    snoop, snooper
    a spy who makes uninvited inquiries into the private affairs of others
    shadow, shadower, tail
    a spy employed to follow someone and report their movements
    a secret listener to private conversations
    type of:
    looker, spectator, viewer, watcher, witness
    a close observer; someone who looks at something (such as an exhibition of some kind)
  3. verb
    watch, observe, or inquire secretly
    synonyms: sleuth, snoop, stag
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    type of:
    monitor, supervise
    keep tabs on; keep an eye on; keep under surveillance
  4. verb
    catch sight of; to perceive with the eyes
    synonyms: sight
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    descry, espy, spot
    catch sight of
    detect, discover, find, notice, observe
    discover or determine the existence, presence, or fact of
    catch out, find out
    trap; especially in an error or in a reprehensible act
    detect some circumstance or entity automatically
    find an instance of (a word or particular usage of a word)
    discover traces of
    observe as if with an eye
    type of:
    comprehend, perceive
    become aware of through the senses
  5. verb
    catch sight of
    synonyms: descry, espy, spot
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    type of:
    catch sight of; to perceive with the eyes
  6. verb
    secretly collect sensitive or classified information; engage in espionage
    spy for the Russians”
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    type of:
    enquire, inquire, investigate
    conduct an inquiry or investigation of
Word Family

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