What Does "Desu" Mean in Japanese?

Written By JASON .

If you're learning Japanese, you've probably come across the word "desu" (です) quite a bit. It's one of the most common words in the language, appearing in everything from basic phrases to polite conversation. But what exactly does it mean? Let's break it down!


The Meaning of "Desu" (です)

At its core, "desu" is a copula—a word that links a subject to a description, similar to the English "to be" (is, am, are).

However, I prefer the translation “it is”.

For example:
✅ これは本です。 (Kore wa hon desu.) → "This is a book."
✅ 彼は先生です。 (Kare wa sensei desu.) → "He is a teacher."

Here, "desu" functions like "is" in English. It connects the subject with a noun or adjective, making the sentence complete.

Is "Desu" the Same as "To Be"?

Not exactly. Unlike English, "desu" does not change based on the subject (I, you, he, etc.), and it doesn't indicate existence.

For example:
🚫 "Desu" does NOT mean "exists."

  • If you want to say "There is a cat," you wouldn't use "desu." Instead, you'd use "imasu" (います) or "arimasu" (あります) depending on the context.

✅ 猫がいます。 (Neko ga imasu.) → "There is a cat."

The Politeness of "Desu"

One important thing about "desu" is that it makes a sentence polite. Without it, a sentence can sound casual or even incomplete.

Compare:

  • これは本です。 (Kore wa hon desu.) → "This is a book." (Polite)

  • これは本。 (Kore wa hon.) → "This a book." (Casual)

The second sentence is grammatically fine but sounds informal, like something you'd say to a close friend.

When NOT to Use "Desu"

While "desu" is common, it doesn’t always appear where you might expect.

  1. With Verbs → You don’t use "desu" with verbs because Japanese verbs already contain tense and formality.

    • 🚫 "食べますです" (Tabemasu desu) → (Incorrect)

    • ✅ "食べます" (Tabemasu) → (Correct, polite) → "I eat."

  2. With "I-adjectives" → In Japanese, adjectives can function as verbs, so adding "desu" after certain adjectives isn't always necessary.

    • ✅ 寒いです。 (Samui desu.) → "It is cold." (Polite)

    • ✅ 寒い。 (Samui.) → "It’s cold." (Casual)

Casual Forms of "Desu"

In informal speech, "desu" can be replaced or omitted. Some casual alternatives include:

  • だ (da) → The informal version of "desu."

    • 彼は先生だ。 (Kare wa sensei da.) → "He is a teacher." (Casual)

  • Nothing at all → In very casual speech, people often drop "desu" entirely.

    • これは本。 (Kore wa hon.) → "This a book."

Conclusion

"Desu" is a simple but essential word in Japanese. It acts like "is" in English, adds politeness, and helps form complete sentences. However, it doesn’t work with verbs, and in casual speech, it can be replaced or omitted.

Next time you're practicing Japanese, try using "desu" correctly to sound polite and natural! 😊


Also if you want a very simple way of learning japanese then be sure to check out the sushilingo app :)

JASON .