What does spy mean?
Spy has two closely related meanings. As a noun, it refers to someone who secretly gathers information, usually on behalf of a government, organization, or private individual. Such a person may operate abroad, infiltrate a group, or obtain confidential details. As a verb, to spy on someone means to secretly observe or monitor them, often in a way that suggests improper or intrusive surveillance. Spy can also mean to look around secretly or search a place, though this sense is less common. The word often appears in contexts involving intelligence, secrecy, betrayal, and political conflict, but its figurative use is broad: anyone who watches others closely or tries to discover what they are doing can be called a spy. Its historical association with espionage has made it a useful term for describing the gathering and concealment of information.
A person who secretly obtains and reports information for another person or organization.
"The government accused the diplomat of being a spy."
The word often implies clandestine or unauthorized activity, although it can also refer to an authorized intelligence operative.
To secretly observe, monitor, or investigate someone or something.
"She suspected that her neighbor was spying on her."
Spy on is the usual construction for covert monitoring. The more formal sense of looking around or searching a place is comparatively uncommon.
The standard plural of the noun spy is spies. It is pronounced /spaɪz/.
"The two spies exchanged information in a crowded market."
A spy’s most valuable currency is often not money or power, but information other people assume is secret.
Reviewed by Deb Chak, Editor. AI-assisted content curated by RJS Tech Solutions LLP.
Etymology of spy
The English word spy comes through Middle English from Old French espier, meaning to observe or watch. Old French espier developed from a Germanic root represented by Frankish *spehōn, related to words such as German spähen, Dutch spieden, and the archaic English espy. The noun spy was likewise shaped by French usage, while espionage and espionage-related forms entered English through French and Dutch traditions rooted in the same Germanic verb.
Related word forms
How spy is actually used
In its noun sense, spy is often used figuratively for someone who secretly watches or investigates. The verb spy on commonly means to covertly monitor another person, while the less common sense meaning to look around is more formal and somewhat literary.