From Middle English spien, aphetic variant of earlier espien ("to espy"), from Old French espier, from Frankish *spehōn, from Proto-Germanic *spehōną, from Proto-Indo-European *speḱ-.

The noun displaced native Old English sċēawere (literally “watcher”), which was also the word for "mirror." In this sense, the verb displaced Old English sċēawian, which was also the word for "to watch" and became the Modern English word show.

• IPA: /spaɪ/

spy (plural spies)

1. A person who secretly watches and examines the actions of other individuals or organizations and gathers information on them (usually to gain an advantage).

   Synonyms: espy, intelligencer, Thesaurus:spy

   • 1941, Theodore Roethke, “Feud”, in Open House; republished in The Collected Poems of Theodore Roethke, 1975, →ISBN, page 4:

     The dead leap at the throat, destroy
     The meaning of the day; dark forms
     Have scaled your walls, and spies betray
     Old secrets to amorphous swarms.

2. (American football) A defensive player assigned to cover an offensive backfield player man-to-man when they are expected to engage in a running play, but the offensive player does not run with the ball immediately.

• French: espion, espionne
• German: Spion, Spionin, Spitzel (colloquial), Schlapphut (colloquial), Schnüffler (colloquial)
• Italian: spia
• Portuguese: espião
• Russian: шпио́н
• Spanish: espía, chivato

spy (spies, present participle spying; simple past and past participle spied)

1. (intransitive) To act as a spy.

   During the Cold War, Russia and America would each spy on each other for recon.

2. (transitive) To spot; to catch sight of.

   I think I can spy that hot guy coming over here.

   • 1536 June 16 (Gregorian calendar), Hugh Latimer, “Sermon II. Master Latimer’s Discourse on the Same Day in the Afternoon [Preached to the Convocation of the Clergy, before the Parliament Began, the Sixth Day of June, the Twenty Eighth Year of the Reign of the Late King Henry VIII].”, in The Sermons of the Right Reverend Father in God, Master Hugh Latimer, Bishop of Worcester. […], volume I, London: […] J. Scott, […], published 1758, →OCLC ↗, page 32 ↗:

     VVherefore lift up your heads, brethren, and look about vvith your eyes, ſpy vvhat things are to be reformed in the Church of England.

     The spelling has been modernized.

   • 1720, Jonathan Swift, A Letter to a Young Clergyman:

     One in reading, skipped over all sentences where he spied a note of admiration.

3. (intransitive) To search narrowly; to scrutinize.
   • c. 1603–1604 (date written), William Shakespeare, “The Tragedie of Othello, the Moore of Venice”, in Mr. William Shakespeares Comedies, Histories, & Tragedies […] (First Folio), London: […] Isaac Iaggard, and Ed[ward] Blount, published 1623, →OCLC ↗, [Act III, scene iii], page 324 ↗:

     (As I confeſſe it is my Natures plague / To ſpy into Abuſes, and of my iealouſie / Shapes faults that are not)

4. (transitive) To explore; to see; to view; inspect and examine secretly, as a country.

• spyglass
• spyware

• French: espionner
• German: ausspionieren
• Italian: spiare
• Portuguese: espiar, espionar
• Russian: шпио́нить
• Spanish: espiar

• German: erspähen
• Italian: spiare
• Spanish: avistar