1. (v. t.) To gain sight of; to discover at a distance, or in a state of concealment; to espy; to see.

2. (v. t.) To discover by close search or examination.

3. (v. t.) To explore; to view; inspect; and examine secretly, as a country; -- usually with out.

4. (v. i.) To search narrowly; to scrutinize.

5. (n.) One who keeps a constant watch of the conduct of others.

6. (n.) A person sent secretly into an enemy's camp, territory, or fortifications, to inspect his works, ascertain his strength, movements, or designs, and to communicate such intelligence to the proper officer.

CIA man agent be vigilant be watchful beagle behold betrayer blab blabber blabberer blabbermouth bug case catch sight of clap eyes on cloak-and-dagger operative counterintelligence agent counterspy delator descry detect detective dig out discern discover distinguish double agent espionage agent espy eye eyeball ferret out fink fish out follow gaze at glimpse grub up have a looksee have in sight hold in view hunt out identify informer inside man intelligence agent investigator keep in sight keep in view keep under observation ken lay eyes on look after look at look on look upon make a reconnaissance make out meddle military-intelligence man narc naval-intelligence man nose notice observe operative peacher peek peep perceive pick out pick up play the spy pry pry out put under surveillance recognize reconnoiter reconnoiterer regard root out scout scout out search out secret agent see sense sight sleuth snitch snitcher snoop spook spot spotter spy out spy upon spy-catcher squealer stag stake out stool pigeon stoolie take in talebearer tattler tattletale telltale twig undercover man view watch whistle-blower witness