The systematic use of spies to get military or political secrets.

Roget 441: vision, sight, optics, eyesight.    view, look, espial^†, glance, ken [Scot.], coup d'oeil [Fr.]; glimpse, glint, peep; gaze, stare, leer; perlustration^†, contemplation; conspection^†, conspectuity^†; regard, survey; introspection; reconnaissance, speculation, watch, espionage, espionnage [Fr.], 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 etc. 443; 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 [Myth.].    ... show more

Roget 461: inquiry; request etc. 765; search, research, quest, pursuit etc. 622.    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 etc. (consideration) 451.    scire facias [Lat.], ad referendum; trial.    questioning etc. v.; interrogation, interrogatory; interpellation; challenge, examination, cross-examination, catechism; feeler, Socratic method, zetetic philosophy^†; leading question; discussion etc. (reasoning) 476.    reconnoitering, reconnaissance; prying etc. v.; espionage, espionnage [Fr.]; 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 etc. (discord) 713; plain question, fair question, open question; enigma etc. (secret) 533; knotty point etc. (difficulty) 704; quodlibet; threshold of an inquiry.    [person who questions] inquirer, investigator, inquisitor, inspector, querist^†, examiner, catechist; scrutator scrutineer scrutinizer^†; analyst; quidnunc [Lat.] etc. (curiosity) 455.    ... show more

Dutch: wie niet waagt, wie niet wint, spionage
Polish: szpiegostwo