Other forms: spies, spying, spied
A spy is somebody who secretly gathers information for another country. A foreign spy, a spy ring, spying on them.
The real work is far duller than fiction suggests: most of it is recruiting and running sources, and most intelligence comes from open material anybody could read. Spying carries the heaviest penalties in most legal systems. Note that the word came from a Frankish verb meaning to watch.
1nounspySomebody who secretly gathers information for another country.
“During the war, she worked as a spy, sending secret messages to London.”
2verbwatchTo watch somebody secretly.
“The neighbours spied on us from behind their curtains.”
Too few real examples of this word to estimate which sense is commonest.
spy is a secret agent.
Old French espier comes from a Frankish verb meaning to watch, from a root meaning to see. Espy and spectacle come from related watching.
Proto-Indo-European
*speḱ- — to look
Proto-Germanic
*spehōną — to see, look
Frankish
*spehōn — to spy
Old French
espier — to spy
Middle English
spien
English, today
spy
Built from
From Middle English spien, aphetic variant of earlier espien (“to espy”), from Old French espier (“to spy”), from Frankish spehōn (“to spy”), from Proto-Germanic spehōną (“to see, look”), from Proto-Indo-European speḱ- (“to look”). Akin to German spähen (“to spy”), Dutch spieden (“to spy”). The noun displaced native sċēawere, which was also the word for "mirror." In this sense, the verb displaced sċēawian, which was also the word for "to watch" and became the Modern English word show. Distant cognate vie PIE with Latin speculātor, Ancient Greek κατάσκοπος.
Etymology from Wiktionary, CC BY-SA