Whether you speak English or French, chances are you’ve heard the expression “je ne sais quoi” used in a variety of situations. Today, we explain all about the origins and meaning of “je ne sais quoi”, which happens to be one of the oldest French expressions still used today.

What does the expression “je ne sais quoi” mean?

Because of its long history, the expression “I don’t know what” can have two radically opposed meanings depending on the way and the situation in which it is used.

The literal meaning of “je ne sais quoi”

If we take the expression word for word, “je ne sais quoi” is said when we want to mean that we don’t have the answer to something, or that we are not able to explain and/or describe it. In this sense, the expression can be translated as “I don’t know what” in English. 

Examples:

Il a perdu son portefeuille qui contenait sa carte bleue, ses papiers d’identité, de l’argent liquide et je ne sais quoi d’autres. => He lost his wallet which contained his credit card, his ID, some money and I don’t know what else. 

Quelque chose s’est produit hier, même si je ne sais pas encore quoi. => Something happened yesterday, even though I don’t know what yet.

Je cherchais je ne sais quoi lorsque le coup de feu retentit. => I don’t know what I was looking for when the shot rang out.

The symbolic meaning of “je ne sais quoi”

Through the export of French cultural works internationally, the expression has begun to have another meaning for the general public. According to the dictionary.com definition, “je ne sais quoi” is used to evoke a quality that is difficult to describe, often very positive. Used in this way, the expression becomes a classic noun phrase that can be used as a subject or as an object.

Examples:

J’ai eu un coup de foudre pour cette fille. Elle a ce petit “je ne sais quoi” qui m’a fait chavirer. => It was love at first sight with this girl. She has that little “je ne sais quoi” which made me fall for her.

La Provence comprend de nombreux villages médiévaux qui possèdent tous une âme unique et un certain “je ne sais quoi”. => The Provence region has many medieval towns which all have a unique soul and a certain “je ne sais quoi”.  

Where does the expression “je ne sais quoi” come from?

Despite its recent international popularity over the last two centuries, the expression “je ne sais quoi” is actually several thousand-year-old. In fact, it has its roots in Latin and Old French. According to its etymology, “je ne sais quoi” comes from the Old French “ne sai quoi” which meant “something”. 

This phrase is itself a translation of the Latin expression “inane nescio quia” first found in one of the 37 volumes of the encyclopedia L’Histoire Naturelle, published in 77 BC by Pliny the Elder (Roman writer, philosopher, historian, and naturalist). Like the French version, the Latin origins of “je ne sais quoi” gave rise to the Spanish (un “no sé qué”) and Italian (un “non so che”) versions of the expression, which are also used in the same way.

The French version of the expression began to be introduced into the English language in the 17th century when the author Thomas Blount chose to include the expression in his work Glossographia. In this work, which could be described as a dictionary, the British author compiles and explains the foreign terms and expressions found in the English language.

How is “je ne sais quoi” used in the world?

We notice that the French expression is used very differently in English and in French.

The use of the expression “je ne sais quoi” in English

In other countries, especially in the United States and the United Kingdom, “je ne sais quoi” is always used as a noun phrase to designate something that is difficult to express and/or describe. The expression is then exclusively introduced by determiners like “a” (“un” in French), and by possessive adjectives like “his/her” (“son/sa” in French).

Examples

She has a “je ne sais quoi” in her voice that makes her sound confident and glamour. => Elle a un “je ne sais quoi” dans la voix qui lui donne un ton confiant et glamour.

The more I think about it, the less I remember her little “je ne sais quoi”. => Au plus j’y pense, au moins je me souviens de son petit “je ne sais quoi”. 

In the Anglo-Saxon culture, the expression is often associated with the French woman, and more specifically with the chic and glamorous actresses of the 60s like Brigitte Bardot or Catherine Deneuve. Thus, “je ne sais quoi” is very often used to state an almost mystical quality in a woman, whether physical or mental. 

The use of the expression “je ne sais quoi” in France 

A “je ne sais quoi” is also said in French, although the expression is rarely used in everyday language. You are more likely to hear it at a high-society dinner than at a family meal.

If we put aside its use as an expression, you will hear the verbal group “je ne sais quoi” used in all sorts of ways in the French language. In this case, an adverb is usually added before the “quoi” to finish marking the negation, like “plus” or “pas”, or to show the frequency and/or the temporality of the sentence with an adverb like “encore”.

Examples:

Je suis perdu dans la vie. Je ne sais plus quoi faire. => I’m lost in life. I don’t know what to do anymore.

Je viens juste de commencer mon nouveau travail. Je ne sais pas encore quoi faire. => I just started out at my new job. I don’t know what to do yet.

How do you write “je ne sais quoi”?

“I don’t know what” is composed of the first-person singular subject personal pronoun “je”, the negative adverb “ne”, the first person singular present tense verb “sais” and the relative pronoun “quoi”.

The wrong ways to write “je ne sais quoi”

Due to its high international popularity, you will often come across misspelled versions of the phrase “je ne sais quoi”. Some of the most common ones include:

  • Jenesequa
  • Je nai se quois
  • Je ne sais qua
  • Je ne sais quo
  • Je ne sais quos
  • Je ne say qua

Thus, the expression “je ne sais quoi” would have become so popular abroad that it appears every year among the most searched French queries on Google by English speakers.

If you want to work on your pronunciation of the French expression while discovering new songs, we recommend the rap song by the artist from Marseille Deen Burbigo called “Un je ne sais quoi”, or the song “Je ne sais quoi” by the Icelandic group Héra Björk, who used the expression during their performance at the Eurovision 2010.

Now, you know the meaning of Je ne sais quoi! As always, if you want to expand your knowledge of the French language, don’t hesitate to read our other articles on the subject of the most famous French expressions such as “Oh là là!“, “Touché” or “C’est la vie“.

Translated into English by Sacha