Have you ever heard two people described as as thick as thieves and wondered what it really means? The phrase paints a picture of friends who share everything, including secrets. Let’s explore its meaning, origin, and use.
In short, the thick as thieves meaning describes a very close, secretive bond between people. This guide covers the definition, the French roots, real examples, and handy synonyms. By the end, you will use the idiom with confidence.
Thick As Thieves Saying
The thick as thieves saying describes people who are extremely close and loyal to each other. Speakers often use it for friends, family members, or partners who trust one another completely and rarely leave each other’s side.
However, the phrase also carries a playful hint of secrecy. Thieves must trust each other, or their plans fall apart. That logic explains why people picked this image to describe tight, secretive bonds and shared goals.
Thick As Thieves Definition
Dictionaries define thick as thieves as very friendly, intimate, or closely allied. The phrase works as an adjective phrase and usually follows the verb “to be.” For example, you can say two friends “are thick as thieves.”
In simple terms, it means “very close.” Some people also use the shorter form without the first “as.” Both versions mean the same thing, though the full version, as thick as thieves, sounds slightly more traditional.
Is As Thick As Thieves an Idiom or Proverb?
It is an idiom, not a proverb. An idiom has a figurative meaning that differs from its literal words, while a proverb offers advice. Nobody learns a life lesson from this phrase; they simply picture closeness.
More precisely, it is a simile because it compares people to thieves using “as.” Therefore, you can call it an idiomatic simile. This label helps when you study figurative language or teach English to new learners.
Thick As Thieves Phrase Structure and Grammar
The thick as thieves phrase follows a simple pattern: subject, verb “to be,” then “as thick as thieves.” You can also use “get” or “become” to show change. For instance, two coworkers might “get as thick as thieves” after a big project.
Also, remember that “thieves” stays plural because the idiom refers to a group. Singular forms like “thick as a thief” sound unnatural and confuse readers. Keep the original wording, and your sentence will read smoothly.
What Does It Mean to Say Thick As Thieves?
When people say two individuals are thick as thieves, they describe a strong, unbreakable bond. The relationship can be a close friendship, a family tie, or a work partnership. Trust and intimacy sit at its core.
These people stick together through good times and bad. They defend each other in disputes and show up when life gets tough. Naturally, outsiders notice this closeness quickly. Above all, they keep each other’s best interests at heart.
Positive Meaning of Thick As Thieves
In its positive sense, the idiom celebrates loyalty and inseparable friendship. Two childhood friends who share jokes, secrets, and dreams fit this description perfectly. Their closeness feels warm, safe, and genuine to everyone around them.
Families use it, too. A grandmother and granddaughter who bake together every Sunday might truly be thick as thieves. Here, the “secret” is merely a shared joy, so the overall tone stays affectionate and light.
Negative Meaning of Thick As Thieves
On the darker side, the idiom can describe people who collude for selfish gain. Politicians, business partners, or officials who protect each other’s wrongdoing may be called thick as thieves. The phrase then hints at corruption or unethical teamwork.
Context decides the tone. If a speaker smiles while saying it, the phrase sounds friendly. When the speaker frowns, it sounds like a warning. Therefore, always check the surrounding words and tone before judging the speaker’s intent.
Thick As Thieves Origin and Etymology
The thick as thieves origin traces back to French. The original saying, “s’entendre comme larron en foire,” literally means “to get along like thieves at a fair.” It dates to roughly the 18th century and later crossed into English.
Fairs drew big crowds, so pickpockets likely worked together there, sharing signals and loot. Their teamwork made them seem inseparable. That vivid picture of cooperating thieves eventually became a shorthand in everyday speech for very close partners.
How the Thick As Thieves Idiom Evolved in English
English speakers adopted the idea and adjusted the wording. “Thick” already meant “intimate” or “friendly” in older English, so the phrase felt natural. Over time, “thick as thieves” became the common, standard version in everyday English.
Today, the idiom appears in novels, news stories, and casual chats. Its meaning shifted slightly, too. Modern speakers now focus more on closeness than on crime, although the playful hint of secrecy still quietly lingers.
Thick As Thieves and Honor Among Thieves
Many readers link this idiom to “honor among thieves,” and the link makes sense. Both phrases suggest that even criminals follow a code of loyalty. That code keeps the group strong and its secrets safe.
Still, the two phrases differ in focus. “Honor among thieves” stresses loyalty and rules, while as thick as thieves stresses emotional closeness. You could say honor holds a gang together, and friendship makes people thick as thieves.
How Do You Use Thick as Thieves?
You can use thick as thieves whenever you want to describe a tight relationship. It fits parents and children, coworkers, teammates, and best friends. Even journalists who share tips during an investigation might earn the label.
Criminals planning a shady scheme also fit the phrase, which adds a touch of dark irony. In every case, the idiom signals that the people involved share something very deeply rooted and important to each other.
Thick As Thieves Example Sentences
Examples make the idiom easier to remember and to copy. Read these three sentences below, and notice how the tone shifts from warm, to critical, to wistful. Each one shows a different shade of meaning.
- John and I are as thick as thieves. We go way back to kindergarten and have been inseparable for years.
- Corrupt politicians are as thick as thieves. They’ll stick up for each other while milking government funds for their own benefit.
- Sarah missed the times when she and her sister were as thick as thieves. These days, they barely have the time to talk to each other.
Notice that the first sentence shows affection, the second shows disapproval, and the third shows nostalgia. Therefore, you can adapt the idiom to nearly any mood. Simply choose your subject, your tone, and your context.
Tips for Using Thick As Thieves in a Sentence
First, always keep your audience and register in mind. The idiom is informal, so it suits blogs, emails to friends, and stories. In formal reports or academic papers, choose a plainer phrase such as “closely allied.”
Next, match the tone to your message. Add a warm detail for friendships, or add a pointed detail for corruption. Finally, avoid overusing it, because a fresh idiom loses charm when it appears in every paragraph.
Thick As Thieves in Formal vs Informal Writing
Writers usually treat idioms like this one as informal language. Journalists still happily use it in features, columns, and opinion pieces, yet they rarely place it in hard news, legal documents, or scientific papers.
For spoken English, the idiom works well anywhere. Friends, coworkers, and family members will understand it instantly. In writing, however, consider your reader first, and swap the phrase for a synonym when the setting feels serious.
Common Mistakes With Thick As Thieves
Learners often change the wording, which breaks the idiom. Saying “thick as thief,” “thick like thieves,” or “as close as thieves” confuses listeners. Stick to the exact form, as thick as thieves, for clear communication.
Another mistake involves tone. Some writers use the phrase for casual acquaintances, but it implies deep closeness. Likewise, calling a single person “thick as thieves” makes no sense, because the idiom needs at least two people.
Thick As Thieves in Books, Music, and Pop Culture
The phrase has inspired titles. Megan Whalen Turner released a novel called Thick as Thieves in 2017, part of her Queen’s Thief series. A 2009 heist film with Morgan Freeman and Antonio Banderas used the title in some regions.
These uses show how deeply the idiom lives in English culture. Writers love it because it instantly signals loyalty, mischief, and adventure. As a result, you will spot the phrase in songs, headlines, and show titles.
Thick As Thieves Similar Phrases
If you want variety, plenty of alternatives to thick as thieves exist. Each one carries a slightly different flavor, so choose carefully. Some sound quite formal, while others sound playful or even a bit cheeky.
Below, you will find direct synonyms, related idioms, and a few opposites. Together, they give you a full toolkit for describing close relationships, whether you write a story, an email, or a social media caption.
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Synonyms for Thick As Thieves
Common synonyms include hand in hand, in tandem, cozy with, buddy-buddy, and kissing cousins. For example, “The two designers worked hand in hand” sounds professional, while “They’re buddy-buddy now” sounds casual, light, and friendly.
Other useful options include close-knit, inseparable, and in cahoots. Pick “in cahoots” when secrecy matters, and pick “inseparable” when you want a warm, friendly tone. These small choices sharpen your meaning and help readers feel your tone.
Related Idioms to Thick As Thieves
Several idioms share a similar spirit. “Birds of a feather” describes people with shared traits, “two peas in a pod” stresses similarity, and “partners in crime” highlights shared mischief. Each phrase paints a unique picture of closeness.
Meanwhile, “in cahoots” and “honor among thieves” lean toward secrecy and loyalty. Of all the options, as thick as thieves remains the best choice when you want closeness, loyalty, and a hint of mischief together.
Opposites of Thick As Thieves
Opposite phrases describe people who clash or drift apart. “At each other’s throats” signals fierce conflict, while “at odds” suggests a milder disagreement. Both phrases help when you contrast a former friendship with a current rivalry.
Sarah’s story fits here. She misses the days when she and her sister were thick as thieves, but busy schedules pulled them apart. In that sense, the idiom can also describe a bond that has faded.
The Final Word
The idiom as thick as thieves describes people who share a close, loyal, and slightly secretive bond. It began as a French saying about thieves at a fair, and English speakers kept the vivid image alive for centuries. Today, it works for friends, families, colleagues, and even partners in mischief.
Remember that the phrase is informal, so use it sparingly in serious writing. Choose your tone wisely, and match the context to the meaning. Use the examples and synonyms above to keep your writing fresh and natural. Have you ever used thick as thieves in your own writing? Share your thoughts below.
Thick As Thieves FAQs
What does thick as thieves mean?
It means people share a very close, loyal, and often secretive bond. They trust each other completely and stick together through good and bad times.
Where does thick as thieves come from?
It comes from an 18th-century French saying, “s’entendre comme larron en foire,” meaning “like thieves at a fair.” English speakers later adopted the same image.
Is thick as thieves a negative phrase?
Not always. It can praise loyal friendships, or it can criticize people who collude unethically. Tone and context reveal which exact meaning the speaker intends.
Is thick as thieves formal or informal?
It is informal. Use it in conversation, blogs, stories, and emails, but swap it for a plainer phrase like “closely allied” in serious reports.
What are good synonyms for thick as thieves?
Good synonyms include hand in hand, in tandem, cozy with, buddy-buddy, kissing cousins, close-knit, and inseparable. Pick one that best matches your tone and context.
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