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Definitions

spy

[spahy] / spaɪ /
NOUN
person who secretly finds out about another's business
Synonyms
STRONGEST
agent detective informer investigator mole operative secret agent secret service undercover agent
STRONG
emissary lookout observer patrol plant scout sleeper sleuth snoop spotter watcher
WEAK
double agent espionage agent foreign agent inside agent intelligencer plumber
VERB
secretly follow, watch another's actions
Synonyms
STRONGEST
discover examine scrutinize snoop
STRONG
case eyeball glimpse meddle notice observe peep pry reconnoiter scout search shadow sleuth spot stag tail trail view watch
WEAK
catch sight of fish out get a load of keep under surveillance look for recon set eyes on stake out take in take note
Antonyms
STRONG
ignore miss neglect overlook

Example Sentences

Examples are provided to illustrate real-world usage of words in context. Any opinions expressed do not reflect the views of Dictionary.com.

Gavalas told Gemini it should have a human on its side, like a spy.

From The Wall Street Journal • Apr. 12, 2026

Meanwhile, Halliday plays Daisy, a recent arrival to the Pearl Girl squad who is really there as an undercover spy for the Gilead’s resistance group, Mayday, under the guidance of June.

From Los Angeles Times • Apr. 8, 2026

It's well known the US regularly flies a U-2 spy plane from RAF Akrotiri, though it's not publicly acknowledged.

From BBC • Mar. 30, 2026

Russia on Monday kicked out a British diplomat over allegations he was working as a spy -- charges rejected by London as "complete nonsense".

From Barron's • Mar. 30, 2026

In his apartment, he made clever spy gadgets, crafting pencils with hidden chambers under removable erasers, cutting hidden compartments into cuff links and batteries.

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

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