Synonyms and related words :
CIA man, asker, catechist, cloak-and-dagger operative, counterintelligence agent, counterspy, cross-interrogator, cross-questioner, detective, double agent, espionage agent, examiner, inquirer, inquisitionist, inquisitor, inside man, intelligence agent, interlocutor, interpellator, interrogator, interrogatrix, interviewer, military-intelligence man, naval-intelligence man, operative, opinion-sampler, poller, pollster, prober, querier, querist, questioner, questionist, quizzer, reconnoiterer, sampler, scout, spotter, spy, spy-catcher, undercover man