That’s a Negatory: Adding くない to Adjectives for Negation :Boy, do we have a useful lesson for you today! By now, you’re probably familiar with Japanese adjectives and how to describe things with them. Today, however, we’re going to learn how to describe what something is NOT! In this lesson, we will be focusing on i–adjectives only and how to attach くない (kunai) and くありません (kuarimasen) to them in order to express the negative form.

Contents
Japanese I-Adjective Review
Before we begin, let’s take a minute to review some useful adjectives. There are two different types of adjectives in Japanese: i–adjectives and na–adjectives. I-adjectives end with the hiragana character い (i), and na–adjectives end with the character な (na). Today, however, we will only focus on i–adjectives. Let’s take a look at some examples below.
Japanese | Romaji | English |
安い | yasui | cheap |
暑い | atsui | hot (weather) |
甘い | amai | sweet |
厳しい | kibishii | strict |
狭い | semai | narrow |
Now that we’ve familiarized ourselves with a few i–adjectives, let’s create some sentences!
今年の先生は厳しいですね!
Kotoshi no sensei wa kibishii desu ne!
The teacher this year is strict, isn’t she!
今日は暑いね!
Kyou wa atsui ne!
Today is hot, don’t you think!
The Negative Form of Japanese I–Adjectives

The negative form of an adjective expresses what the noun after it is NOT. When conjugating i–adjectives into their negative form, you simply remove the い at the end of the word and replace it with くない (kunai).
After adding くない, the i–adjective remains an i-adjective and functions the same as any other i-adjective. You can place it before a noun to modify it (e.g. 悪くない犬 (warukunai inu, a dog that isn’t bad), or you can place it at the end of a sentence. Placing a くない adjective at the end of a sentence is for casual situations.
Let’s take the i–adjectives from above and turn them into their negative form below.
Japanese | Romaji | English |
安 | yasu | cheap ➝ not cheap |
暑 | atsu | hot (weather) ➝ not hot |
甘 | ama | sweet ➝ not sweet |
厳し | kibishi | strict ➝ not strict |
狭 | sema | narrow ➝ not narrow |
Now that we know how to change i-adjectives into their negative form, let’s make some sentences! In the first set of sentences, we will add the くない adjective to the end of the sentence, giving it a casual tone. In the second set, we will put the くない adjective somewhere in the center to show how it can modify a noun (just like regular i–adjectives).
1. Example sentences (adjective at the end of the sentence):
このホテルは安くないよ!
Kono hoteru wa yasukunai yo!
This hotel isn’t cheap!
今年の夏はあまり暑くないね。
Kotoshi no natsu wa amari atsukunai ne.
The summer this year isn’t very hot.
日本のケーキはあまり甘くないよね。
Nihon no keeki wa amari amakunai yo ne.
The cake in Japan isn’t very sweet.
Example sentences (adjective used to modify nouns):
私は厳しくない先生が好きです。
Watashi wa kibishikunai sensei ga suki desu.
I like teachers who aren’t strict.
[Lit. “I like non-strict teachers.”]
彼の彼女は狭くない部屋に住みたいです。
Kare no kanojo wa semakunai heya ni sumitai desu.
His girlfriend wants to live in an apartment that isn’t too small.
[Lit. “His girlfriend wants to live in a not-narrow room.”]
The Negative Form of Japanese I–Adjectives (Formal)
As stated in the previous section, adding a くない adjective to the end of a sentence makes it casual. If you want to make it formal, you don’t add くない. Instead, you add くありません (kuarimasen), which has the same meaning but is used for polite situations.
[WARNING: くありません CANNOT be used to modify nouns. If you want to modify a noun with an i-adjective in its negative form, you MUST use くない!
〇甘くないケーキ (amakunai keeki, cake that isn’t sweet) dc4ddc4d
✖甘くありませんケーキ (amakuarimasen keeki)dc4edc4e]
Let’s take the くない adjectives from the previous section and turn them into their formal counterparts below.
Japanese | Romaji | English |
安 | yasu | not cheap (casual) ➝ not cheap (formal) |
暑 | atsu | not hot (casual) ➝ not hot (formal) |
甘くない ➝ 甘くありません | ama | not sweet (casual) ➝ not sweet (formal) |
厳しくない ➝ 厳しくありません | kibishi | not strict (casual) ➝ not strict (formal) |
狭くない ➝ 狭くありません | sema | not narrow (casual) ➝ not narrow (formal) |
Now that we can conjugate negative i–adjectives into their polite form, let’s create a few sentences!
この車はあまり安くありません。
Kono kuruma wa amari yasukuarimasen.
This car isn’t that cheap. (Formal)
外ではあまり暑くありません。
Soto de wa amari atsukuarimasen.
It’s not that hot outside. (Formal)
Correct:
〇私は狭くない部屋の方が好きですけど、あまり厳しくありません。dc4ddc4d
Watashi wa semakunai heya no hou ga suki desukedo, amari kibishikuarimasen.
I like rooms that aren’t small the best, but I’m not that strict. (Formal)
Incorrect:
✖私は狭くありません部屋の方が好きですけど、あまり厳しくありません。dc4edc4e
Watashi wa semakuarimasen heya no hou ga suki desukedo, amari kibishikuarimasen.
In Summary
In order to conjugate i-adjectives into their negative form, you simply remove the hiragana character い from the end and replace it with くない.
I-adjectives in their くない form can be used to modify nouns (just like regular i–adjectives), or they can be used at the end of a sentence to make it casual.
In formal situations, くありません is used instead of くない. I-adjectives in their くありません forms CANNOT be used to modify nouns.
Now that you know how to say what something is NOT, it’s time to get out there and practice!
Remember, when learning a new language, there is nothing more important than to practice the new information you learn. You don’t want to forget, now, do you?
Learn Japanese negative form with BondLingo?
