Every era has its own way of describing the person who tells the authorities what everyone else was trying very hard not to say out loud. Today, we might hear “informant,” “confidential source,” “whistleblower,” or “snitch,” depending on whether the speaker is a police officer, a journalist, a lawyer, or someone who just got caught doing something extremely explainable but not exactly admirable.
But older English slang had a whole carnival of names for informants. Some sounded like animals. Some sounded like nursery-school insults. Some sounded like they escaped from a smoky back room where everyone wore hats, whispered dramatically, and said things like “the coppers are wise.” These old-timey slang terms for informants reveal more than just colorful language. They show how people have long thought about secrecy, loyalty, betrayal, law enforcement, and the awkward social position of the person who “sings.”
Below are 12 vintage slang terms for informants, including words from American underworld slang, British criminal argot, old police vocabulary, and everyday speech. Some are still understood today. Others have retired to the linguistic attic, probably next to a fedora and a suspiciously heavy briefcase.
What Is an Informant, Really?
An informant is a person who gives information, often to authorities, investigators, journalists, or another party seeking inside knowledge. In ordinary speech, the word can be neutral. A linguistic informant may help a researcher understand a dialect. A police informant may provide information about illegal activity. A workplace informant may quietly report misconduct. Context matters.
Slang, however, rarely stays neutral. Most slang words for informants carry judgment. They suggest betrayal, fear, cowardice, self-preservation, revenge, or clever survival. That is why the vocabulary is so rich. People do not usually invent dozens of colorful terms for something they feel calm about. Nobody says, “Please enjoy my 40 slang terms for a reasonably priced stapler.” But betrayal? Secrets? Someone talking to the police? English speakers have been polishing that vocabulary for centuries.
12 Old-Timey Slang Terms for Informants
1. Rat
“Rat” is one of the most famous slang terms for an informant, and it is still very much alive. To “rat someone out” means to expose them, especially to authorities or to a person in power. The word works because rats have long carried an image problem. Fair or not, they are associated with sneaking, scavenging, and abandoning a sinking ship. Once a person was called a rat, the metaphor did all the heavy lifting.
In older slang, “rat” developed from the idea of deserting or betraying one’s associates. By the early 20th century, it was widely used for someone who informed on others. The word is short, sharp, and wonderfully unpleasant. It lands like a door slam. In fiction, newspapers, gangster movies, and street talk, “rat” became the classic label for a person who broke the code of silence.
Example: “The gang thought Mickey was loyal until he turned rat the minute the detective started asking questions.”
2. Stool Pigeon
“Stool pigeon” is one of the most picturesque old slang terms for informants. The phrase originally referred to a decoy pigeon used to lure other birds. From there, it became a term for a person used as bait or a spy, especially one working with the police. The image is wonderfully old-fashioned: a bird sitting there, pretending to be harmless, while the trap quietly closes.
By the 19th century, “stool pigeon” had moved into criminal and police vocabulary. It often suggested someone planted inside a group to gather information. Unlike “rat,” which focuses on betrayal, “stool pigeon” emphasizes deception. A stool pigeon does not simply talk; he blends in, listens, waits, and reports back. Very dramatic. Very trench coat. Very “meet me under the gas lamp at midnight.”
Example: “The poker room went silent when they realized the new fellow was a stool pigeon.”
3. Stoolie
“Stoolie” is the shorter, snappier cousin of “stool pigeon.” It sounds almost cute, which is part of the fun, because the meaning is not cute at all. A stoolie is an informant, usually one connected with police work or criminal circles. The word became especially common in American slang during the early 20th century.
Old detective novels and film noir dialogue loved words like this because they carried mood instantly. Say “informant,” and you sound formal. Say “stoolie,” and suddenly there is cigarette smoke in the room, rain on the window, and somebody named Eddie looking nervous.
Example: “Louie swore he was no stoolie, but somehow the police knew every detail of the plan.”
4. Snitch
“Snitch” is another classic. It has been used for an informer or tattletale for a very long time, and it remains common in modern English. The word has underworld flavor, schoolyard flavor, and pop-culture flavor all at once. A child can snitch about a stolen cookie. A criminal can snitch to reduce a sentence. A coworker can snitch about who keeps microwaving fish in the office kitchen, which frankly may be a public service.
The word may be connected with older slang involving the nose, which makes sense because informants are often imagined as people who “stick their nose” into other people’s business. “Snitch” is flexible: it can be a noun or a verb, serious or playful, childish or threatening.
Example: “Nobody trusted Benny after he snitched about the card game in the basement.”
5. Fink
“Fink” is a terrific old slang word because it sounds insulting even before you know what it means. In North American slang, a fink can be an informer, a strikebreaker, or a generally contemptible person. Its history is debated, with possible ties to German slang and labor history, but its emotional meaning is clear: a fink is not someone the speaker admires.
In the early 20th century, “fink” became especially associated with labor disputes, strikebreaking, and betrayal of group loyalty. Later, it broadened into a general insult. If someone called you a fink, you were not being invited to brunch.
Example: “The workers called him a fink after he reported the strike plans to management.”
6. Squealer
“Squealer” is one of the most expressive slang terms for an informant. It comes from the verb “squeal,” meaning to cry out in a high-pitched way. Applied to a person, it suggests someone who cannot keep quiet under pressure. The sound imagery is doing all the work: a squealer is not merely speaking; a squealer is making a noisy, embarrassing production of it.
In old crime slang, to “squeal” meant to inform, especially to the police. The term also shows how animal imagery often appears in informant slang. Rats, pigeons, canaries, snakes, and squealers all turn human behavior into a little zoo of disapproval. English, apparently, looked at betrayal and said, “This needs more livestock.”
Example: “The detective did not need much time; the lookout turned squealer before lunch.”
7. Canary
A “canary” is an informant who sings. That is the whole joke, and honestly, it is a good one. Canaries are famous songbirds, and “singing” has long been slang for confessing, revealing secrets, or giving information to police. If a suspect “sings like a canary,” the authorities are getting a full concert.
The term has an almost comic brightness compared with darker words like “rat” or “snake.” Still, it carries the same basic meaning: someone is talking, and someone else is probably not happy about it. The musical metaphor made “canary” especially memorable in crime writing and gangster dialogue.
Example: “Once the bookkeeper started singing like a canary, the whole scheme collapsed.”
8. Nark
“Nark” is an older British slang term for a police spy or informer. It is often seen in the phrase “copper’s nark,” meaning a police informant. The word is not as common in American English, where “narc” usually points toward narcotics enforcement, but “nark” has a long history in British crime slang.
The word has been linked to Romani words connected with the nose, which again fits the larger pattern. Informant slang often imagines the teller as someone nosing around, sniffing out secrets, or poking into hidden business. Whether the person is actually brave, selfish, frightened, paid, pressured, or morally conflicted depends on the story. Slang rarely pauses for nuance; it prefers to throw a tomato and move on.
Example: “The thieves suspected there was a copper’s nark among them.”
9. Narc
“Narc” is a newer-looking word with old-school energy. In American slang, it can refer to a narcotics officer, but it can also mean someone who informs on others, especially to authorities. Because of its connection to drug enforcement, “narc” became especially common in late 20th-century school, street, and pop-culture speech.
Compared with “nark,” “narc” feels more American and more modern, but it belongs on this list because it grew from the same larger tradition: naming the person who alerts authority figures. In everyday teen or campus slang, “narc” sometimes became a broad word for anyone who ruins the fun by reporting rule-breaking. In that sense, the word moved from crime slang into ordinary social life.
Example: “Do not be a narc just because someone brought an extra slice of cake into study hall.”
10. Tattletale
“Tattletale” sounds childish, and that is exactly why it is useful. It describes someone who tells on others, especially over small offenses. Unlike “rat” or “stool pigeon,” it does not always imply police, crime, or serious betrayal. It often belongs to schools, siblings, neighborhoods, and family kitchens.
The word combines “tattle,” meaning idle or revealing talk, with “tale,” meaning a story or report. A tattletale tells the tale that someone else hoped would remain untold. It is one of the gentler words on the list, but anyone who has ever had a sibling announce, “Mom, guess what he did,” knows that gentler does not necessarily mean harmless.
Example: “Clara became the household tattletale after reporting every missing cookie crumb like a tiny courtroom witness.”
11. Grass
“Grass” is British slang for an informant, and “to grass someone up” means to inform on them. The term is often connected with rhyming slang, where “grasshopper” rhymes with “copper,” meaning police officer. Shorten “grasshopper” to “grass,” and suddenly the lawn has become suspicious.
“Grass” has a distinctly British feel, especially in crime dramas and prison slang. It can also appear as “supergrass,” referring to a major informant whose testimony or information implicates many others. While “grass” may sound harmless to American ears, in its slang setting it is sharp, accusatory, and loaded with betrayal.
Example: “The crew blamed Danny for grassing them up after the police arrived with names, dates, and far too much confidence.”
12. Snake in the Grass
“Snake in the grass” is older than most modern crime slang and describes a hidden traitor or secret enemy. As an informant term, it focuses on concealment. The snake is dangerous because it is unseen. The informer is dangerous because no one knows who is reporting back.
This phrase has survived because the image is simple and powerful. A snake in the grass is close enough to harm you but hidden enough that you do not notice until too late. In old underworld slang, it was a natural fit for someone who pretended loyalty while quietly passing along information.
Example: “They searched for the snake in the grass who had warned the authorities before the meeting even started.”
Why So Many Slang Words for Informants?
Language grows fastest around emotion, conflict, and taboo. Informants sit right in the middle of all three. To one side, an informant may help uncover wrongdoing, protect victims, or expose corruption. To another side, the informant may be seen as disloyal, self-serving, frightened, or manipulative. That tension creates vocabulary.
Many old-timey slang terms for informants are built from sound. “Squealer,” “snitch,” “tattletale,” and “canary” all suggest noise. The informant is the one who cannot stay silent. Other terms are built from animals: “rat,” “stool pigeon,” “canary,” and “snake in the grass.” These words turn social betrayal into something visual and instinctive.
There is also a strong pattern of insider versus outsider language. Groups that rely on secrecy often develop their own vocabulary. Criminal circles, prisons, labor movements, political groups, schools, and even families create special terms for people who reveal private information. The slang becomes a warning label: this person cannot be trusted with the group’s secrets.
Old Slang, Modern Lessons
These words may sound funny now, but they point to serious questions. When is telling the truth brave? When is it betrayal? When is silence loyalty, and when is silence protection for bad behavior? A whistleblower who exposes public danger may be praised. A person who lies to reduce personal consequences may be condemned. A child who reports bullying may be doing the right thing. A coworker who spreads private gossip may simply be causing harm.
That is why word choice matters. Calling someone an “informant” sounds official. Calling someone a “whistleblower” may suggest conscience. Calling someone a “rat” or “fink” suggests contempt. The vocabulary does not merely describe the person; it tells the listener how to feel about the person.
Experiences and Reflections: How These Words Still Show Up Today
You do not need to live in a black-and-white detective movie to encounter the social drama behind these old slang terms. Anyone who has gone to school, worked in an office, played on a team, joined a club, or grown up with siblings has seen some version of the “informant problem.” Someone tells. Someone gets in trouble. Someone else says, “Who said something?” Suddenly the room becomes a mystery novel with worse snacks.
One common experience is the schoolyard tattletale. In childhood, the tattletale is often treated as the enemy of fun. Maybe someone passed a note, whispered during silent reading, or smuggled candy into a place where candy was treated like an international security threat. The tattletale reports it, and now everyone is annoyed. But even in that small example, the issue is not always simple. Reporting a harmless prank feels different from reporting bullying, cheating, or something unsafe. The same acttelling an authority figurecan be petty in one case and responsible in another.
Workplaces have their own version. Nobody likes the office “snitch” who reports tiny mistakes just to look good. That person turns a coffee spill into a congressional hearing. But employees who report fraud, harassment, discrimination, theft, or unsafe conditions may be protecting others. The old slang terms do not leave room for that difference. “Rat” is a judgment, not an analysis. That is why modern language often separates “snitching” from “whistleblowing.” One suggests betrayal for selfish reasons; the other suggests disclosure for a larger ethical purpose.
Families also create their own informant vocabulary, even if nobody uses the word “stool pigeon” at the dinner table. A younger sibling who announces every broken rule can become the household “canary.” A cousin who reveals who dented the garage door may be called a “tattletale.” Usually, these moments become funny later, especially once everyone survives the lecture. But they teach an early lesson: information has power. The person who controls the story can change the outcome.
Pop culture keeps these old words alive because they are efficient. In a crime film, “rat” instantly tells the audience there is a code of loyalty. In a comedy, “narc” quickly identifies the rule-enforcer who spoils the party. In historical fiction, “stool pigeon” gives a scene a vintage flavor. These words are tiny time machines. They carry the atmosphere of police stations, union halls, school corridors, smoky clubs, neighborhood gossip, and family kitchens.
The best way to understand these terms is to treat them as cultural clues. They are not just synonyms. Each one reveals an attitude. “Canary” is playful and musical. “Snake in the grass” is suspicious and dangerous. “Tattletale” is childish. “Fink” is contemptuous. “Stool pigeon” is theatrical. “Grass” is regional. Together, they show how English speakers have spent generations wrestling with a messy truth: sometimes people talk, and once they do, everything changes.
Conclusion
Old-timey slang terms for informants are more than dusty dictionary curiosities. They are snapshots of how people judge loyalty, secrecy, authority, and betrayal. Words like “rat,” “stool pigeon,” “snitch,” “fink,” “squealer,” and “canary” survive because they are vivid. They turn social tension into pictures, sounds, and insults that people instantly understand.
Some of these words are funny now. Some still sting. All of them remind us that language is never just decoration. It carries history, attitude, humor, fear, and moral judgment in a surprisingly small package. So the next time you hear someone called a rat, a narc, a tattletale, or a canary, remember: English has been naming the teller for centuries, and it has rarely done so gently.
Note: This article is written for language-history and cultural context. It discusses slang meanings, not legal advice or guidance for real-world disputes.
