What Does Still Waters Run Deep Mean?

Have you been looking for the perfect way to describe a friend, family member, or coworker who’s very quiet yet actually extremely passionate and interesting beneath their shy exterior? You’ve come to the right place! Keep reading to learn all about the idiomatic and proverbial expression still waters run deep.

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What Does Still Waters Run Deep Mean?

As you likely guessed from the introduction, the phrase still waters run deep is used to say that people with shy, reserved dispositions are often very profound, passionate, and intelligent underneath their calm, quiet demeanors—with many interesting ideas and thoughts. Their placid manner hides a subtle nature, or a complexity that is not immediately clear and obvious. In other words, the phrase describes people who have more going on internally than is apparent externally. 

Thinking about it in these ways—what is hidden, exterior versus interior—the comparison to a body of water makes good sense. When you come across still water, there’s typically a lot more going on under the surface than is discernible: When the water appears peaceful and undisturbed, it is usually quite deep; it often extends far below the surface, into dark and mysterious territory. On the contrary, rushing water is typically stirred up and moving fast in shallow areas, where it’s perhaps passing over rocks close to the surface or meeting the shoreline.

Here are some example sentences using the expression still waters run deep:

  • As the saying goes, still waters run deep: She may seem quiet and a bit dull at first, but Kim is actually one of the most interesting and smartest people I know. 
  • Bill’s coworkers are used to it by now. They know that he’s too shy to share his thoughts in company meetings, but that with him, still waters run deep, and he’ll send an email shortly after with profound thoughts and recommendations. 
  • My dad just goes to show that still waters run deep. He has such a calm, mild attitude, but he’s incredibly complex and passionate. You just have to know him well to see a different side.

The Origin of the Phrase

The expression we know and use today appears to have evolved, according to The Concise Oxford Dictionary of Proverbs, from a Latin phrase popular in classical times: altissima quaeque flumina minimo sono labi, which translates to “the deepest rivers flow with least sound.” This earliest version can be found in a history of Alexander the Great by Quintus Rufus Curtius, suggesting its Bactrian origin. (Bactria was an ancient country in what is now part of Afghanistan, Uzbekistan, and Tajikistan.) It may have been first used in English around 1400. 

Although today the saying is used to mean that quiet people are often much more interesting and intelligent than they may seem, it was once used to suggest that those who are calm and placid can be dangerous. This is evident in William Shakespeare’s use of the phrase in his play Henry VI. He wrote:

“Smooth runs the water where the brook is deep;
And in his simple show he harbours treason.
The fox barks not when he would steal the lamb.
No, no, my sovereign; Gloucester is a man
Unsounded yet and full of deep deceit.”

In the late 1400s, the proverb was expanded into a short fable (and was then later included in European collections of the renowned Aesop’s fables). The fable expressed the same earlier interpretation of the expression: Those with little to say can pose a big threat. Of course, this meaning makes good sense, too, as placid, calm water may seem safe on the surface, but what lies below is often deep and thus dangerous territory. A French proverb very similar to the English version of today also leans toward the meaning of hidden danger: il n’est pire eau que l’eau qui dort, or “no water is worse than quiet water.” As already mentioned, however, the phrase has since lost this connotation and come to mean those who are quiet are often very complex and interesting.

Understanding Idioms and Proverbs

Still waters run deep is both an idiom and a proverb. An idiom is a figurative expression with an intended meaning that typically can’t be understood, or at least fully understood, just by looking at the individual words that comprise it. Even if you’ve never heard the term idiom, you have most likely heard many idiomatic expressions. Here are just a few of the most common idioms used today:

You’re in hot water.
His boss gave him the ax.
It’s time to face the music.
You’ve hit the nail on the head.

If you took the first example literally, you’d think it was describing a person standing in a bathtub full of hot water, perhaps. But the expression is actually used to describe a person who’s in trouble. Likewise, rather than literally being handed a tool for chopping wood, if you get the ax from your boss, it means you’re getting fired. It’s time to face the music means that it’s time to come to terms with the consequences of your actions. And when someone has hit the nail on the head, they’ve gotten an answer exactly right or done something exactly as it should have been done.

As mentioned above in the post, the saying still waters run deep does have a literal meaning: It is the case that often a placid surface is hiding deep water underneath. Yet, to take the phrase literally today would be to miss its intended, figurative meaning: That silent people who appear calm and shy on the surface are actually much deeper and complex (just like placid water); that their quiet demeanor hides an interesting, profound, passionate, thoughtful, and intelligent nature.

The well-known expression is also a proverb. A proverb is a short, common phrase or saying that imparts advice or shares a universal truth. Synonyms of the term proverb include adage, aphorism, and maxim. Here are some additional examples of well-known proverbs:

Blood is thicker than water.
A picture is worth a thousand words.
Beauty is in the eye of the beholder.

Of course, still waters run deep isn’t the only popular proverb that encourages us not to jump to conclusions on appearances alone: The saying don’t judge a book by its cover similarly reminds that there’s often more going on under the surface.

Learn the meanings of many more idioms and proverbs here.


The proverb and idiom still waters run deep is used to say that although someone appears shy and quiet on the outside, they may be very interesting and passionate on the inside—that a calm, placid demeanor often hides very complex thoughts and an intelligent nature.