Spies are a perpetual source of fascination in pop culture, from the adventures of James Bond to the travails of KGB agents Phillip and Elizabeth Jennings on The Americans—not to mention real-life tales of dead drops and honey traps. Most people are familiar with terms such as asset, tradecraft, and double agent, but some spy terms are a little more covert. Here’s a look at some clandestine words you should be prepared to disavow completely if questioned.

1. MOLE-CATCHER

Since the 1980s, mole-catcher has been used in relation to the lowest form of mole: the informant. In Gerald Priestland’s 1983 book At Large, he discusses “Mrs Thatcher's mole-catcher, the Mr Bingham of Epsom who is supposed to be plugging the leaks in Whitehall.” A Guardian article from 1986 mentions a downside to catching a sneak: “Prime Ministers were not necessarily overjoyed when the efforts of their mole catchers proved successful. The lurid publicity of a spy trial could be embarrassing.”

2. PHYLACTOLOGY

This word for counterespionage was coined by novelist Kingsley Amis in 1966’s The Anti-Death League: “Apparently what's called the philosophy of phylactology—spy-catching to you—has been transformed.” Amis also coined the rare words phylactological and phylactologist. Given their obscurity, these are perfect words for the spy game. You could put phylactologist on a business card, and no one would blink.

3. QUIET AMERICAN

This phrase is derived from the title to Graham Greene’s 1955 novel The Quiet American, whose protagonist Alden Pyle is a CIA agent in Vietnam.

4. SPIERY

The Oxford English Dictionary defines this obscure word as “The fact or condition of being a spy; the action of spying; espionage.” A mention in the awkwardly titled 1588 book The Troubles of Our Catholic Forefathers Related by Themselves puts the word in disreputable company: “examinations, confessions, fictions, accusations, slanders, spiery, recantation and the like.”

5. PLAY MATERIAL

Since the late 1800s, this has been a term for the harmless stuff given to children as play fodder, such as crayons, paper, and matches. But in the 1960s, another sense developed, retaining the sense of harmlessness. Eric Ambler used the term in his 1969 spy thriller The Intercom Conspiracy: “‘Play material’ was the jargon phrase used to describe the low-grade classified information fed back to the enemy through double agents.”

6. CUT-OUT

While cut-out sounds like more childlike play material, it’s a crucial cog in the machinery of spycraft. In his 1963 book They Call it Intelligence: Spies and Spy Techniques Since World War II, Joachim Joesten describes a cutout as “a trusted middleman.” The idea is compartmentalization, cutting out the spy from some of the risk and the cut-out from too much potentially dangerous information.

7. DISCOVERER

This is one of the most honest and dishonest words for a spy, who does often discover information, though not by the most straightforward means. This term has been describing spies and scouts since the mid-1400s, and it appears in Shakespeare’s Henry IV Part 2: “Here ... send discoverers forth, To know the numbers of our enemies.”

8. WORMING

It’s not unusual to hear someone engaged in slippery, ingratiating behavior described as worming their way into the hearts and minds of their dupes. You don’t often hear worming as meaning the work of spies, but it has occasionally had just this meaning. In Francis Beaumont and John Fletcher’s 1607 play The Woman Hater, spying is referred to as “this worming trade.”

9. SWALLOW

The honey trap or honey pot is one of the most famous espionage strategies: seducing someone as part of a ruse. Hardly an episode of The Americans goes by without one or both of the Jennings honey-trapping some lonely, gullible citizen. In the 1972 book Any Number Can Play, the awesomely named Dennis Bloodworth mentions a related term in a passage trimmed by the OED: “You have doubtless read about the ... ‘swallows’ of the KGB, the young ladies trained ... to bed down intelligence targets, so that they can be comfortably and conveniently bugged and photographed in compromising ... positions?”

10. CRYPTONYM

There are so many -nyms in the vocabulary of names. A pseudonym is an author’s fake name, while an eponym is a word derived from a name. But a cryptonym is far more sly: Since the mid-1800s, it’s been a code name, especially for a spy. An 1862 use in St. James’ Magazine mentions a common feature of spy life: “For a short time he assumed several unobtrusive civilian cryptonyms.”

11. LURCHER

No offense to Frankenstein, but lurching has never had the best reputation. The OED definition explains how this word found itself in the espionage lexicon: “One who loiters or lies hidden in a suspicious manner; a spy.” Other disreputable meanings of lurcher include a cross-bred dog and a swindler. So if a labradoodle ever wants to sell you real estate, beware.