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-catcher, spy out, spy upon, squealer, stag, stake out, stool pigeon, stoolie, take in, talebearer, tattler, tattletale, telltale, twig, undercover man, view, watch, whistle-blower, witness