"software used to obtain covert information about a computer's activities by transmitting data covertly from its hard drive to another computer," by 2000, from spy + ending from software in the computer sense.
1793, from French espionnage "spying," from espionner "to spy," from espion "a spy" (16c.), probably via Old Italian spione from a Germanic source akin to Old High German spehon "to spy" (see spy (v.)). For initial e- see e-. Middle English had espiouress "female spy" (early 15c.).
It forms all or part of: aspect; auspex; auspices; auspicious; bishop; circumspect; conspicuous; despicable; despise; episcopal; especial; espionage; espy; expect; frontispiece; gyroscope; haruspex; horoscope; inspect; inspection; inspector; introspect; introspection; perspective; perspicacious; perspicacity; prospect; prospective; respect; respite; retrospect; scope; -scope; scopophilia; -scopy; skeptic; species; specimen; specious; spectacle; spectacular; spectrum; speculate; speculation; speculum; spice; spy; suspect; suspicion; suspicious; telescope.
It is the hypothetical source of/evidence for its existence is provided by: Sanskrit spasati "sees;" Avestan spasyeiti "spies;" Greek skopein "behold, look, consider," skeptesthai "to look at," skopos "watcher, one who watches;" Latin specere "to look at;" Old High German spehhon "to spy," German spähen "to spy."