espionage(n = noun.act) - the systematic use of spies to get military or political secrets;
is a kind of spying, undercover work
The practice or employment of spies; the practice of watching the words and conduct of others, to make discoveries, as spies or secret emissaries; secret watching. [1913 Webster]
espionage, n. the practice of spying or of using spies, esp. by governments.
Etymology:
F espionnage f. espionner f. espion SPY
N vision, sight, optics, eyesight, view, look, espial, glance, ken, coup d'oeil, glimpse, glint, peep, gaze, stare, leer, perlustration, contemplation, conspection, conspectuity, regard, survey, introspection, reconnaissance, speculation, watch, espionage, espionnage, autopsy, ocular inspection, ocular demonstration, sight-seeing, point of view, gazebo, loophole, belvedere, watchtower, field of view, theater, amphitheater, arena, vista, horizon, commanding view, bird's eye view, periscope, visual organ, organ of vision, eye, naked eye, unassisted eye, retina, pupil, iris, cornea, white, optics, orbs, saucer eyes, goggle eyes, gooseberry eyes, short sight, clear sight, sharp sight, quick sight, eagle sight, piercing sight, penetrating sight, clear glance, sharp glance, quick glance, eagle glance, piercing glance, penetrating glance, clear eye, sharp eye, quick eye, eagle eye, piercing eye, penetrating eye, perspicacity, discernment, catopsis, eagle, hawk, cat, lynx, Argus, evil eye, basilisk, cockatrice, seeing, visual, ocular, optic, optical, ophthalmic, clear-eyesighted, eagle-eyed, hawk-eyed, lynx-eyed, keen- eyed, Argus-eyed, visible, visibly, in sight of, with one's eyes open at sight, at first sight, at a glance, at the first blush, prima facie, Int, look!, the scales falling from one's eyes, an eye like Mars to threaten or command, her eyes are homes of silent prayer, looking before and after, thy rapt soul sitting in thine eyes.
N inquiry, request, search, research, quest, pursuit, examination, review, scrutiny, investigation, indagation, perquisition, perscrutation, pervestigation, inquest, inquisition, exploration, exploitation, ventilation, sifting, calculation, analysis, dissection, resolution, induction, Baconian method, strict inquiry, close inquiry, searching inquiry, exhaustive inquiry, narrow search, strict search, study, scire facias, ad referendum, trial, questioning, interrogation, interrogatory, interpellation, challenge, examination, cross-examination, catechism, feeler, Socratic method, zetetic philosophy, leading question, discussion, reconnoitering, reconnaissance, prying, espionage, espionnage, domiciliary visit, peep behind the curtain, lantern of Diogenes, question, query, problem, desideratum, point to be solved, porism, subject of inquiry, field of inquiry, subject of controversy, point in dispute, matter in dispute, moot point, issue, question at issue, bone of contention, plain question, fair question, open question, enigma, knotty point, quodlibet, threshold of an inquiry, inquirer, investigator, inquisitor, inspector, querist, examiner, catechist, scrutator scrutineer scrutinizer, analyst, quidnunc, inquiry, inquisitive, requisitive, requisitory, catechetical, inquisitorial, analytic, in search of, in quest of, on the lookout for, interrogative, zetetic, all searching, undetermined, untried, undecided, in question, in dispute, in issue, in course of inquiry, under discussion, under consideration, under investigation, sub judice, moot, proposed, doubtful, quaere?, what?, why?, wherefore?, whence?, whither?, where?, how comes it?, how happens it?, how is it?, what is the reason?, what's the matter?, nicht wahr?, what's in the wind?, what on earth?, when?, who?.