Beginner’s Guide to Japanese Adjectives: な and い Adjectives

Last Updated on 06.01.2022 by Coto Japanese Language School

Once you get the hang of basic Japanese grammar structure, you will want to form more complex sentences. After all, you’re not going to master the Japanese language by just learning how to say “それはいぬです” (that is a dog). What happens if you want to say that the dog is cute? Or short? Or friendly? This is where Japanese adjectives come in: to make you express more, rather than just stating the obvious. (Sure, that is a dog, but what about it?)

Japanese adjectives aren’t just used to describe physical appearance or behavior. They’re used as quantifiers — to express emotions and detail dimensions. They’re used to modify a noun. While they function similarly to English, the grammar rules of Japanese adjectives are a little bit complex, too.

This will be a self-study guide on Japanese adjectives, complete with example sentences. We’ll talk you through the two kinds of adjectives and how to use them, but if you want to get more support and direction from native instructors, we suggest you take a look at our online Japanese course.

Before we go further into the article, note that this article will mostly use hiragana, so prior knowledge of them is a must. If you’re still learning them, don’t worry — take a look at our hiragana chart to review them.

Tyes of Japanese Adjectives (And How to Use Them)

Japanese adjectives are categorized into two: な-adjectives and い-adjectives. Their main function is to describe nouns, but these adjectives can also be transformed into nouns themselves.

The easiest way to separate な-adjectives and い-adjectives is by checking the adjective’s ending. More precisely, if the word ends with い or not. Of course, this is a rule of the thumb, but there are exceptions you need to note as well. What you need to note are the grammar particles and changes (to past, negative or past-negative forms) — what’s required to join an adjective to a noun.

We’ll be introducing a few Japanese vocabularies, so make sure you know all the basic Japanese words before moving forward. We have like, a hundred of them (yes, literally).

japanese i adjective

い-adjectives in Japanese

The い-adjective is easy to identify: they end in い and are written in hiragana. Some い-adjectives might also have a double い (い), but its stem form will usually stay the same regardless of the form it takes.

In this case, we’ll be using the example 高い (たかい), which means high (height) or expensive (price). Briefly, this is how you will transform an い-adjective into different tenses and forms.

Positive (Present)高いたかいHigh
Negative (Present)高くないたかくないNot high
Positive (Past)高かったたかかったWas high
Negative (Present)高くなかったたかくなかったWas not high

Present Tense for I-adjectives

To express an い-adjective in the present tense, simply let it take its original stem form and add an 〜い (already joined). A tricky thing to keep in mind is that the Japanese language doesn’t recognize present and future tense. Rather, they consider it one. Take a look at the sentence below.

The weather is nice today.

The weather (will be) nice tomorrow.

Negative (Present) Tense for I-adjectives

To make a present-tense い-adjective negative, replace the 〜い with 〜くない

さむ → さむくない

It is not cold today.

Past Tense for I-adjectives

To express an い-adjective in the present tense, you must omit the 〜い from the word’s stem form and join it with a 〜かった.

たか → たかかった

That car was expensive.

Negative (Past) Tense for I-adjectives

For this, similar to negative and past adjectives, you can change the 〜い with a new conjugation, which is a combination of くない and かった: くなかった.

たか → たかくなかった

Exceptions and What You Need to Know for I-adjectives

Remember what we say about stem forms for adjectives will stay the same regardless of the form and tense it takes? There’s one exception to the rule: the Japanese adjective いい (good; well).

Why? The word, in its kanji form, is written 良い, which can also be read as よい (yoi). When it’s in a positive and present tense, you can use either one and it’ll be as fine (although よい has a more formal sound to it). However, when you want to transform the word to negative or past tense, the stem word becomes よ instead of

Positive (Present)良いよい;いいGood; well
Negative (Present)良くないよくないNot good
Positive (Past)良かったよかったWas good
Negative (Present)良くなかったよくなかったWas not good

The same thing can be said with かっこいい. When it becomes a negative form or past tense, the stem changes to よ. Instead of かっこいくない, change it to かっこよくない.

One last thing: also it seems like it, きれい (pretty or clean) and きらい (hate or dislike) is actually a na-adjective even though the word ends with , so be careful!

Yasai ga kirakunai.
I don’t hate vegetables. (Wrong)

Yasai ga kirai ja nai.
I don’t hate vegetables. (Correct)

Casual Form for I-adjectives

For the polite form of い-adjective, you will need to add the auxiliary verb of です. For negative and past adjective forms, follow the same conjugational transformation as well.

FormCasual FormPolite formMeaning
Positive (Present)よいよい;いいですGood; well
Negative (Present)よくないよくないですNot good
Positive (Past)よかったよかったですWas good
Negative (Present)よくなかったよくなかったですWas not good

Making it a casual form is easier; simply remove the です and leave it as it is. However, note that this only applies when the adjective is put at the end of the sentence.

A lot of Japanese people will even shorten the adjective and omit the . For example, when talking with friends in a good mood, people will say すげー instead of すごい to express something amazing, or うまー instead of うまい to compliment a very delicious meal.

japanese na adjective

な-adjectives in Japanese

Unlike い-adjectives, you can’t modify conjugations in な-adjectives directly to express tense or form. Instead, think of them as nouns (although they’re not, so be careful). This is because the way you modify its value is the same as how you would with nouns. What you want to do instead is to change the auxiliary verb of the whole sentence or phrase:です、ではありません、 でした or ではありませんでした.

The way you can identify a な-adjective is by looking at the particle attached to it: な. For example, 元気人・げんき人, which means a healthy (or happy, depending on the context) person. A lot of people find な-adjectives to be easier to learn because of their simple (and easy modification) rule.

Like い-adjectives, you can put a  な-adjective before a noun. When you do so, the adjective-noun combination becomes the subject.

Adjective + + Noun + です | ではありません | でした | ではありませんでした

You can also put a な-adjective at the end of a sentence. When that happens, the form is like this:

Adjective + です | ではありません | でした | ではありませんでした

In this case, we’ll be using the example 元気, which means happy or healthy. Briefly, this is how you will transform an な-adjective into different tenses and forms.

Present Tense for Na-adjectives

The most basic form of な-adjectives — meaning, positive value in the present tense — is followed by the auxiliary verb of です (polite) or だ (casual). Keep in mind that, similar to い-adjectives, present and future tense uses the same form. To describe a noun, you need to put the particle な in the middle of the adjective and the noun (hence, it’s called na-adjective). Take a look at the example below.

Positive (Present)元気だげんきだHealthy; lively
Negative (Present)元気じゃないげんきじゃないNot healthy; lively
Positive (Past)元気だったげんきだったWas healthy; lively
Negative (Present)元気じゃなかったげんきじゃなかったWas not healthy; lively

The person I like is Tanaka-san.

As we mentioned before, the conjugation rules for な-adjectives are the same as nouns, so even when the adjective is put at the end of the sentence, you will still use だ.

I like Tanaka-san.

Negative (Present) Tense for Na-adjectives

Similarly, too conjugate the auxiliary verb to get to the negative form for な-adjective, add 〜じゃありません. You can also use 〜ではありません that has the same meaning (negative value), but sounds more polite and is usually used in written Japanese.

To make it casual, you can shorten it into 〜じゃない or 〜ではない.

That waiter is not kind to guests.

Because I don’t sing so much, I’m not good at karaoke.

You can also put a negative な-adjective before a noun.

Unhealthy people are not allowed to enter the cafe.

Past Tense for Na-adjectives

To indicate that something was true before (and is not now), you will need to add だった (casual) or でした (polite) at the end of the sentence or phrase with a な-adjective.

That person was once a famous singer.

When I was a kid, I hated taking a bath.

Negative (Past) Tense for Na-adjectives

As with previous Japanese adjective modification, to make a Na-adjective negative and in the past tense, simple add じゃありませんでした or ではありませんでした

You can make it more casual by just transforming the auxiliary verb like this:

じゃありませんでした  → じゃなかった
ではありませんでした → ではなかった

This town wasn’t peaceful (before).

Before the renovation, the hotel wasn’t pretty.

Casual Form for Na-adjectives

We’ve touched up how to change polite forms to casual forms for な-adjective, but we’ve made a table to sum it all up.

FormCasual FormPolite Form
Positive (Present)元気だ元気です
Negative (Present)元気じゃない元気じゃありません
Positive (Past)元気だった元気でした
Negative (Present)元気じゃなかった元気じゃありませんでした

Exceptions and What You Need to Know for Na-adjectives

You can immediately modify な-adjectives into a negative value, past tense — or both and join it with a noun. However, keep in mind that this is only applicable if you use casual auxiliary verbs.

Here are a few examples:

Genki ja nai hito. (Correct)

Genki ja arimasen hito. (Wrong)

Genki datta hito. (Correct)

Genki deshita hito. (Wrong)

Another thing to keep in mind is an exception: the Japanese adjective おなじ・同じ. Even though it is technically a な-adjective, you will have to remove the な when you combine it with a noun.

You are as tall as I am.



Learning to modify and use Japanese adjectives might seem tedious, but a few exceptions and grammar notes still make it a tricky thing to tackle. When you want to use Japanese adjectives to color your sentences, be careful not to treat い-adjectives and な-adjectives the same way.

What’s next after learning Japanese adjectives? Make your conversation more interesting and descriptive by taking look at our guide to top basic Japanese adverbs you need to know.

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