As Thick As Thieves (Meaning & Origin!)

To be “as thick as thieves” means to be very close friends. Two people who are inseparably close, who share lots of secrets together. This is not to be confused with the common British use of “thick” to mean stupid. The phrase was originally a French expression that was translated to English.

It’s easy to confuse this one since there are a number of expressions, at least in British slang, relating “thick” to being stupid.

Thick in this sense is about being deep in with someone, being extremely close, even being inseparable.

It’s an interesting expression with a fairly long history, so let’s find out more.

What does “as thick as thieves” mean?

To be “as thick as thieves” means that two people are extremely close or have an extremely close relationship.

It evokes the sense that two thieves, or indeed any two criminals engaged in criminal acts, are “thick” together because if one of them goes down they both go down.

They must have each other’s backs otherwise it’s mutually assured destruction.

Today, the general sense though is simply that two people are very close friends.

It’s not really the kind of thing you might use for romantic partners, although you certainly could. It’s really a bit more specific than that.

It implies a kind of partnership—such as two actual thieves might have.

Of course, in general, people don’t imply much by it other than that two people are very good friends.

However, it may of course also have more specific implications.

Take, for example, two particularly mischievous kids.

They are always up to something, they’re inseparably close, and they always find themselves getting into trouble together.

They are as thick as thieves in the most fundamental sense.

They spend their time together and they get into trouble together.

On the other hand, though, it can be a more general expression meaning two people are close friends.

“Jim and Andy have been as thick as thieves ever since they were little,” for example.

It doesn’t imply anything beyond the fact that they are close friends.

So, historically of course the phrase had a more specific meaning.

It definitely retains that meaning to an extent today, but we are less concerned with roving thieves than we once were.

Thus, its application has widened.

Nonetheless, its origin is a fascinating insight into its modern usage.

Where does “as thick as thieves” come from?

As I mentioned, the expression was originally a French one, which ran s’entendre comme larron en foire—“like thieves at a fair”.

Our oldest written example of this expression comes from a short story by French Honoré de Balzac, published in 1837.

We can surmise, then, that the expression long predates this.

In fact, this in turn seems to come from the Latin proverb: Intelligunt se mutuo, ut fures in nundinis—“a thief knows a thief as a wolf knows a wolf”.

Ultimately, then, this was translated into English as “as thick as thieves”.

In English we have records going back to around the early 19^th Century of its use in novels and short stories.

So, again, the phrase had likely already been translated into English before Balzac’s collection of stories was even published.

Back then, in English, it certainly had the sense of two people who may be up to no good.

It developed to mean simply two people who are very close, although that meaning was certainly coming through at this point.

In other words, it’s an extremely old expression in one form or another, having been passed down from a Latin proverb that is probably close to two millennia old.

What exactly does the word “thick” imply in this context?

What does “thick” mean in slang?

Thick can have a couple of slang meanings so it’s important to clear that up.

The more common meaning today, as you probably know, is “stupid”.

To be thick is to be dim-witted or unintelligent.

But that is certainly not the implied sense here.

It’s a rather old idiomatic and semi-metaphorical expression relating to being “in the thick of it”.

Imagine someone with “thick” hair—that hair is all very clumped close together.

The same is essentially true of people who are “thick as thieves”.

They are extremely close together and bound tight.

It’s that sense, again, of being bound to one another in some way.

Thieves are bound together by their own mutual criminal acts.

How would you use the phrase “as thick as thieves”?

The simplest way to use the phrase is about two people who are very close.

“Those two are as thick as thieves, always have been,” for example.

All this really means is that the two are very close friends.

On the other hand, you might use it to imply something more about the relationship.

“Those two have been as thick as thieves ever since they arrived. What are they up to?” for example.

The phrase here is implying there’s something more to the relationship and something more going on.

Again, though, the far more common way of using the expression is simply to mean two people are close friends.

Thick in the sense of as thick as thieves is evoking the sense, perhaps, of being “in the thick of it” with someone.

You are both so close that you are basically bound together, inseparable and close knit.

It’s important not to get this confused with the perhaps more common slang expression where “thick” means that someone is stupid.

You are thick together—you are not thick yourself.

More in Phrase Meanings

• As Thick As Thieves
• As Thick As Two Short Planks
• Bigger Fish To Fry
• Bob’s Your Uncle
• By The Skin Of Your Teeth
• Dressed To The Nines
• The Pen Is Mightier Than The Sword