Secret Messages: Spy & Code Vocabulary 

Have you ever wondered how governments can code secret messages to prevent enemy nations from learning their plans—or how their opponents can sometimes break the codes and gain a critical advantage?

Do you enjoy reading spy stories, but find the vocabulary difficult?

You can learn some of that vocabulary here, and then read a few fascinating stories that also can help you remember the new words.

After links to several stories about spies, read about secret codes and people who developed or decoded them. Finally, there’s a Secret Messages Crossword. (Use the links above to take you to each section more quickly.)

title & 2 pictures: of a frog 'spy' hiding in a marsh and using binoculars, &  of 3 'spies'-- men in suits with big pictures of an ear, an eye, & a mouth instead of heads.

Espionage & Secret Message Vocabulary Explained

First, here are a few intelligence agency acronyms used in these articles. (Acronyms are names made up of the first initials of words.) 

  • The CIA (Central Intelligence Agency) is the foreign spy agency of the United States. 
  • The FBI (Federal Bureau of Investigation) is concerned with tracking criminal, spy, or terrorist activity within the U.S.
  • The KGB (which translates into English as the Committee for State Security) was the USSR’s security and spy agency during the Cold War. (It was the agency opposing the CIA in the Moscow articles below.)
  • M15 & M16 are British counterintelligence and security agencies that were involved in some of stories of spying during world War II below.
  • The SOE (Special Operations Executive) was a British agency directly involved in spying and sabotage in German-occupied Europe during World War II.
  • The OSS (Office of Strategic Services) was the main U.S. spy agency in World War II. (When it was shut down, its spy operations became the basis for the CIA.)

To bug is to install electronic devices in a building, on a phone line (or elsewhere*) to listen in (eavesdrop) on the conversations of enemies or rivals.

Diplomatic embassies located in enemy nations (like U.S. diplomats in Moscow or Russian diplomats in the U.S.) often find their host company has tried to bug their embassies in order to spy on them. The host countries also may suspect that some diplomatic staff are probably spies.

*Unlikely objects can be bugged. The Mental Floss article linked below mentions a coat and typewriter keys that were bugged.

A cipher is a number or other symbol used in code—or more recently the key that enables decoding. ‘Cipher’ comes from the Arabic word for zero.

A code is a set of rules for secret messages that allow people to transmit communications that can be read (using a special decoder) by others in their group but cannot be understood by their enemies or rivals.

In wartime governments go to great efforts to develop codes that cannot be broken or cracked (figured out) by enemy codebreakers

(Another meaning of code is a set of principles to live by, for example a school’s honor code—rules that forbid cheating on exams.)

To code can mean to write instructions for computers in a “language” they understand.

To encode is to translate a message into a special code, and to decode is to translate it back into normal words.

To encrypt and decrypt mean the same as en- and decode.

A cryptographer is someone who is trained to figure out (decode) the secret messages of enemy nations. (Crypto comes from the Greek, and then the Latin, word for something hidden.)

Espionage is a formal word for spying.

A handler is the person who manages a network of spies.

To infiltrate is to secretly enter enemy territory (often to spy or cause damage). 

Informants are people who provide a spy agency with information that they claim is true.

Intelligence can mean information collected by spying, (as well as intellectual ability).

To intercept is to obtain an enemy message before it can reach the people it was intended for.

An operative is a person carrying out their agencies’ operations (usually spying or other secret activities that are harmful to their opponents. We don’t use the word for people doing for an agency’s routine or normal business.)

Surveillance means keeping a close, constant watch on someone.

The Ducksters (children's) website has an excellent explanation in very simple English of the purpose of spying and information about spying during World War II.

Practice your understanding of this secret message vocabulary—as well as more common words also related to spying and secret messages-- with a crossword puzzle.

Mid-Twentieth Century Spy Stories

You can see this spy vocabulary—and more—in use and read (and/or hear) some astonishing stories in the articles linked below.

NPR tells the story of the CIA in Moscow during the Cold War, and especially of one agent who pretended to be just a party-loving embassy office worker-- and of the CIA spymasters who helped her and other spies.

(Tony and Jonna Mendez were real-life equivalents of the fictional “Q,” and recently got clearance to publish a book about their story—just before Tony died of cancer. Their lives were amazing; Tony also helped rescue American diplomats when the Iranians captured the American embassy in 1980.)

To find out what happened to ‘Party Marti’ you’ll need to read the article.

You can listen to it (it’s about 7 1/2 minutes) instead of reading it—but doing both is excellent English practice!

The Guardian has short accounts with pictures of 10 of the best spies from World Wars I & II and the Cold War plus Belle Boyd (a spy for the Confederates during the American Civil War) and Queen Elizabeth I’s spymaster from th 1500s.

The Atlantic article is longer but it gives the nail-biting details about the women who spied for the Allies during World War II, especially those in occupied France.

Working with or in the French Resistance, they took astonishing risks, but their work saved countless lives of French and British civilians as well as Allied soldiers. 

You can read the stories of several in detail, including Virginia Hall (below), Marie-Madeleine Fourcade, the head of one French Resistance operation, and Jeannie Rousseau, a brilliant woman with a photographic memory who worked as a translator for the Germans.

Rousseau said later, “’I could not but hear what was said. And what they did not say, I prompted.” She was briefly shown plans for the top-secret new rockets the Germans were developing. She memorized them, later wrote down everything she had seen, and then waited and hoped the British would believe the message she sent at such a risk.

They did believe it. They destroyed the German factory at Peenemunde before it could produce those terrible rockets. 

Later Rousseau was captured and sent a concentration camp. The story of her survival there is also hard to believe. (A Washington Post interview with her tells the whole story of her career as a spy, her survival, and her quiet life afterward.

It’s long (almost 5,000 words), though the English isn’t hard. (I checked. Almost 95% of the words are in the 3,000 most common words in English—and you’ve just learned some of its less common words.)

I hesitated to include it because of the length, but it’s an unforgettable tale if you can find the time for it.

Virginia Hall was an American spy with a wooden leg she called ‘Cuthbert.’ Posing as a newspaper reporter, Hall was actually a liaison officer with the very risky task of connecting with the Resistance in Lyon (although she did not know anyone there when she arrived.)

She accomplished more than her handlers had even hoped she could, escaped after being arrested, and finally was ‘exfiltrated’ (helped to escape from France. It’s the opposite of ‘infiltrated.’)

Just before D-Day, she went back in and worked with the Resistance to cut German communication lines. She also resumed spying. From the Atlantic article: “Disguised as a milkmaid, she sold cheese and eavesdropped on the German Seventh Army, which, Purnell writes, helped ‘pave the way for the Allied recapture of Paris.’ ”

Decoders & Code Talkers

The Smithsonian has an article on American women codebreakers during and after World War II.  They were important to the war effort, although the government agencies responsible for decoding were reluctant to hire them at first.

Codebreaking is a very slow process that can often result in dead ends, even after months of work. The description of their persistence and occasional genius is fascinating.

I was even more interested to learn more about the Navajo Code Talkers. Because Navajo is a difficult language that few outsiders have learned, it made an ideal basis for the Marine’s communication system in the Pacific during World War II.

Navajo Code Talkers could keep the leaders of different units informed about troop movements and battles without the enemy learning that important information.

The Code Talkers created a special secret code based on Navajo, but with added code words for military equipment using Navajo names for different animals and birds. (The names of different birds stood for different types of aircraft.)

Code Talkers were attached to individual Marine units, so they could safely pass their secret messages from one group to another. The Japanese were never able to crack the code. The Code Talkers’ Commanding Officer said that without them, the Marines could never have won the fight for Iowa Jima.

Most Americans knew nothing about their activities until years after the war, when the operation was finally declassified (removed from top secret status).

The CIA has a very interesting web page that not only discusses the history of the Code Talkers, but also provides a limited Navajo dictionary and invites readers to decode a sample message.

Spy, Codes, & Decoding Vocabulary Practice

You can download a Spies & Secret Messages Crossword here. Its answers are here.

Related Pages:

'Printable Crossword Puzzles: 20+ puzzles to make earning academic vocabulary fun' + picture of a crossword puzzle

Crossword Puzzles are a great way to make vocabulary study more fun. These can be printed for practice offline.

20+ Words for Truth, Falsehood, & Error

Abraham Lincoln picture & quote: 'No man has a good enough memory to be a successful liar.'

Learn and practice the words for truth-- and for various forms of falsehood.

'Practice Academic Vocabulary with this Historic Speech' with a photo of John F. Kennedy speaking.

You can review (or learn) & practice a lot of academic vocabulary in this 1961 Kennedy speech.

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