In any language, there are various parts of speech that perform different but important functions. Parts of speech include: nouns, verbs, adjectives, etc. In this article we’ll zoom in on adjectives: description words.
Adjectives are important for giving objective and subjective information about things. If I say “I’m using the white cup,” you can distinguish it from other cups. If I say “the coffee is hot,” you know to be careful before taking a sip. And if I say “the coffee is delicious,” even if you disagree, you’ll know about my subjective tastes.
So, if you want to be able to clearly describe items or express your feelings in Japanese, you’ll want to know adjectives!
Adjectives in English vs. Japanese
Often adjectives in Japanese are used in similar sentence structures to those in English. For example, in English we can create these two similar phrases: “ramen is delicious” and “delicious ramen.” In Japanese:
ラーメンはおいしい。
ra-men wa oishii.
= ramen is delicious.
おいしいラーメン。
oishii ra-men.
= delicious ramen.
Here you can see that, while Japanese grammar overall differs from English, these structures when using adjectives are almost the same.
However, adjectives in Japanese do have significant deviations from those in English in the form of “adjective conjugations.”
In English, we usually either conjugate verbs or add more words to express different ideas, such as saying “it was hot” or “it is not hot.” In Japanese, though, you’d need to conjugate the adjective “hot” to make the equivalent phrases. (It is hot = atsui. It was hot = atsukatta. It is not hot = atsukunai.)
The rules for conjugation depend on which type of adjective you’re using.
Types of adjectives in Japanese
There are two types of adjectives: い-adjectives (i-adjectives) and な-adjectives (na-adjectives). The category an adjective falls under will determine how it’s used grammatically.
い-adjectives are so named because:
1. they all end in an い hiragana
2. that い will change in some way depending on the grammar. Words like おいしい (oishii = delicious), かわいい (kawaii = cute) and 大きい (ookii = big) are all い-adjectives.
The other category are the な-adjectives. All adjectives that don’t end in い are automatically な-adjectives. This includes words like 元気 (genki = energetic), 上手 (jouzu = skillful), and 静か (shizuka = quiet).
You may have noticed that those words do not end in a な hiragana. Rather, な is a particle used together with な-adjectives in some grammar structures.
I want to warn you that although the vast majority of adjectives that end in い are い-adjectives, there are exceptions. Common ones include きれい (kirei = pretty or clean), 有名 (yuumei = famous), and 得意 (tokui = skillful, similar to “jouzu”). If an adjective ends with い but that い doesn’t stick out when the word is written in kanji, that adjective will be a な-adjective.
Nouns used as adjectives
I also want to warn you that, while there are only two categories of adjectives, there is another interesting case. You may have seen description words use a の (no) particle. For example, with many color words you’ll use の. (Such as green shirt = midori no shatsu, and brown hair = chairo no kami.)
While it seems counter-intuitive, and these words can be adjectives in English, they are not adjectives in Japanese. They are actually nouns.
Their grammar works the same way as other times we use the の particle:
日本の文化
nihon no bunka
= Japanese culture
アニメのキャラ
anime no kyara
= an anime character
These kinds of nouns are easy to mix-up with な-adjectives (and their grammar is actually similar). But if you’re ever unsure which category a word belongs to, check the dictionary. Takoboto.jp and jisho.org will tell you if a noun is prone to being used like an adjective.
Conjugation of い-adjectives
All い-adjectives end in an い hiragana. And for all conjugations of い-adjectives, you’ll remove the い and add a new ending.
Here’s a chart detailing how you would conjugate these five adjectives into negative and past tense forms:
| Positive/Dictionary Form | Negative form | Past tense form | |
| Conjugation Rule | N/A | remove い, add くない | remove い, add かった |
| delicious | おいしい (oishii) | おいしくない(oishikunai) | おいしかった(oishikatta) |
| cute | かわいい(kawaii) | かわいくない(kawaikunai) | かわいかった(kawaikatta) |
| big | 大きい(ookii) | 大きくない(ookikunai) | 大きかった(ookikatta) |
| hot | あつい (atsui) | あつくない(atsukunai) | あつかった(atsukatta) |
| sweet | 甘い(amai) | 甘くない(amakunai) | 甘かった(amakatta) |
It’s very important that you remove the い ending, but many beginner students forget to do so. The main reason is that many い adjectives end with an extended “i” sound. We see that in words like おいしい and かわいい.
Since there’s still a remaining “i” sound, it’s not as obvious that the い hiragana was removed from the end. In order to make the change from the conjugations more obvious, I included the words あつい and 甘い which don’t have an extended “i” sound.
This also acts as a reminder to be careful of spelling! Not including the final い hiragana in positive/dictionary form is also a common mistake with beginner students.
Almost every conjugation with an い-adjective will involve adding a “k” sound afterwards. Adding く is especially recurrent.
Watch out for いい!
The adjective いい (ii = good) is a fairly common word. It’s also used to make compound words like 頭がいい (atama ga ii = smart) and かっこいい (kakkoii = cool).
However, its conjugations are a bit irregular. Rather than being able to directly conjugate いい, first you must change いい into the equivalent meaning word よい (yoi). (While いい and よい mean the same thing, using よい outside of conjugations may sound old-fashioned.)
After you change いい into よい, you can follow the usual い-adjective conjugation rules and get the correct forms! For example, with negative form: いい ➞ よい ➞ よくない.
This also applies when conjugating compound words with いい. You’ll only focus on conjugating the いい part of the word. The chart below demonstrates:
| Positive/Dictionary Form | Negative form | Past tense form | |
| Conjugation Rule | N/A | remove い, add くない | remove い, add かった |
| good | いい (ii) | よくない(yokunai) | よかった(yokatta) |
| smart | 頭がいい(atama ga ii) | 頭がよくない(atama ga yokunai) | 頭がよかった(atama ga yokatta) |
| cool | かっこいい(kakkoii) | かっこよくない(kakkoyokunai) | かっこよかった(kakkoyokatta) |
Extra importance of い-adjective conjugations
While い-adjective conjugations are obviously important when using い-adjectives themselves, the same conjugation rules come up in different situations as well.
Anything with a negative ない (nai) ending (whether い-adjectives, な-adjectives, nouns, or verbs) can be used with stacking conjugations by following い-adjective conjugation rules. It’s the same with たい endings.
This can be seen when conjugating anything into negative past tense form. First you’ll conjugate into negative tense with a ない ending. Then you’ll follow the い-adjective past tense rule: remove い, add かった. Here are a couple examples:
食べない ➞ 食べなかった
tabenai ➞ tabenakatta
= I don’t eat ➞ I didn’t eat.
あつくない ➞ あつくなかった
atsukunai ➞ atsukunakatta
= It isn’t hot ➞ It wasn’t hot.
Conjugation of な-adjectives
Since な-adjectives have no common ending among them, there’s nothing that could consistently be removed. Instead conjugations of な-adjectives simply involve adding new endings.
Actually, nouns “conjugate” the same way as な-adjectives! This allows you to say things like “It’s not fish” or “It was a test.”
Here are the same forms but with a selection of な-adjectives and nouns:
| Positive/Dictionary Form | Negative form | Past tense form | |
| Conjugation Rule | N/A | add じゃない | add だった (casual) OR add でした (polite) |
| energetic | 元気 (genki) | 元気じゃない(genki janai) | 元気だった / 元気でした (genki datta/genki deshita) |
| pretty or clean | きれい(kirei) | きれいじゃない(kirei janai) | きれいだった / きれいでした (kirei datta/kirei deshita) |
| famous | 有名(yuumei) | 有名じゃない(yuumei janai) | 有名だった / 有名でした (yuumei datta/yuumei deshita) |
| fish | 魚 (sakana) | 魚じゃない(sakana janai) | 魚だった / 魚でした (sakana datta/sakana deshita) |
| test | テスト(tesuto) | テストじゃない(tesuto janai) | テストだった / テストでした (tesuto datta/tesuto deshita) |
Using な-adjectives effectively
Since with な-adjective conjugations you only need to add something rather than manipulate the word, many learners prefer them when learning conjugation rules, since that’s more similar to English.
However, な-adjectives throw a curveball in the cases where you need to include the particle な.
The main situation is when you put a な-adjective in front of a noun. With い-adjectives, you can put them in front of a noun as-is:
おいしいラーメン。
oishii ra-men.
= (It’s) delicious ramen.
However, if you put a な-adjective instead, you must include a な between the words:
有名なラーメン。
yuumei na ra-men.
= (It’s a) famous ramen.
As one more example of using a な-adjective before a noun:
静かなところ。
shizuka na tokoro.
= (It’s a) quiet place.
This な particle also comes up with the grammar points ので, meaning “because”, and のに, meaning “despite.” When using an い-adjective, sentences with those look like this:
おいしいので食べました。
oishii node tabemashita.
= Because it’s delicious, I ate it.
おいしいのに食べなかったです。
oishii node tabemashita.
= Because it’s delicious, I ate it.
However, when using a な-adjective, you have to add な after the adjective:
有名なので見ました。
yuumei na node mimashita.
= Because it’s famous, I saw it.
有名なのに見なかったです。。
yuumei na noni minakatta desu.
= Because it’s delicious, I ate it.
The inclusion of the な particle doesn’t affect the meaning, but it is unfortunately just one of those things you have to know in order to speak Japanese properly. Forgetting it is similar to saying “buyed” instead of “bought”; you’ll probably be understood, but it will be clear you’re not as familiar with the language.
Comparative and superlative
You could argue that English does have adjective conjugations with the comparative and superlative forms.
Comparative form allows you to relatively “compare” the qualities of different things. You’ll typically add an “er” ending to change an adjective into this form, for example “bigger” and “easier.“
Superlative form is used to express that something has the “most” of that quality. You’ll usually add “-est” to the end of the word. We then get words like “biggest” and “easiest.”
Somewhat ironically, Japanese does not have adjective conjugations to express these ideas. Instead, you use comparison words and phrases. These are examples using the equivalent words to “more” and “most” (although there are other ways):
象がもっと大きい。
zou ga motto ookii.
= Elephants are more big.
➞ Elephants are bigger.
クジラが一番大きい。
kujira ga ichiban ookii.
= Whales are the most big. (literally “number one big”)
➞ Whales are the biggest.
Common adjectives for everyday use
We’ve gone in-depth with some of the rules of Japanese adjectives. Now it’s time for practical application! Here is a list of common adjectives of both types. After that, there are several example sentences to give you some guidance on making your own.
い-adjectives:
いい (ii) = good (*be careful with conjugations!)
悪い (warui) = bad
大きい (ookii) = big
小さい (chiisai) = small
高い (takai) = high, tall, or expensive
低い (hikui) = low to the ground
安い (yasui) = cheap
おいしい (oishii) = delicious
甘い (amai) = sweet
辛い (karai) = spicy
やさしい (yasashii) = kind, nice (personality)
危ない (abunai) = dangerous
こわい (kowai) = scary
すごい (sugoi) = amazing
面白い (omoshiroi) = funny, interesting
難しい (muzukashii) = difficult
な-adjectives:
簡単 = kantan = easy, simple
元気 = genki = energetic
上手 = jouzu = skillful
便利 = benri = convenient
きれい = kirei = pretty or clean
有名 = yuumei = famous
好き = suki = likable
きらい = kirai = unlikable
Positive form sentences:
ケーキはおいしい。
ke-ki wa oishii.
= Cake is delicious.
日本での電車は便利です。
nihon no densha wa benri desu.
= Trains in Japan are convenient.
かわいい猫ですね！
kawaii neko desu ne!
= That’s a cute cat!
面白い映画だった！
omoshiroi eiga datta!
= It was an interesting movie!
簡単なテストでした！
kantan na tesuto deshita!
= That was an easy test!
While these last two sentences are in past tense, the adjectives themselves are in present positive form.
Negative form sentences:
このカレーはあまり辛くない。
kono kare- wa amari karakunai.
= This curry is not very spicy.
ホラー映画が好きじゃない。
hora- eiga ga suki janai.
= I don’t like horror movies.
高くないホテルに泊まりたい。
takakunai hoteru ni tomaritai.
= I want to stay at a hotel that’s not expensive.
有名じゃないところ。
yuumei janai basho.
= (It’s) not a famous place.
きらいじゃないけど、あまり好きじゃない。
kirai janai kedo, amari suki ja nai.
I don’t hate it, but I don’t really like it.
Past tense form sentences:
It is possible to use a past tense form adjective before a noun, and you wouldn’t use the な particle in that case. Doing so would qualify as modifying a noun with a phrase, which translates as: “(thing) that (modifying phrase)”.
However, it’s typically more natural to put the past tense conjugation at the end.
ケーキはおいしかった。
ke-ki wa oishikatta.
= The cake was delicious.
映画は面白かった！
eiga wa omoshirokatta!
= The movie was interesting!
テストは簡単でした！
tesuto wa kantan deshita!
= The test was easy!
難しかった時。
muzukashikatta toki.
= (It was) a time that was difficult.
有名だったところ。
yuumei datta tokoro.
= (It was) a place that was famous.
Adjectives as interjections
Hopefully the example sentences weren’t too complicated, but you may still have reservations on creating sentences like those on your own.
If so, I want to give this encouragement while shedding light on a value and norm in Japanese communication.
In Japanese, there is more emphasis on displaying active listening by saying short interjections. These can include words like なるほど (naruhodo) and そっか (sokka) that demonstrate understanding or agreement, but it can also include adjectives!
For example:
いいですね。
ii desu ne.
That’s good.
すごい！
sugoi!
Amazing! / Wow!
おもしろい！
omoshiroi!
That’s funny! / That’s interesting!
Hearing these phrases encourages your conversation partner by letting them know you’re engaged. It’s an easy way to get them to elaborate on their story.
Using adjectives to react to things in your environment is also an easy way to foster a connection with nearby people. If you say おいしい (oishii = delicious) while eating food, they may express agreement or give suggestions for other things you may like. If you say 難しい (muzukashii = difficult) while trying to do something, they’ll express sympathy and may try to help you.
Japanese culture is very focused on community, and even by expressing your feelings very simply, you can better cultivate that bond.
Put adjectives into action
Adjectives are a crucial part of communication, especially in Japanese. There are many rules to keep in mind, especially how grammar varies with い-adjectives vs. な-adjectives. Whether you’re speaking at a beginner or advanced level, adjectives are always important in Japanese.
It takes time and practice to become comfortable with adjective conjugations. This is why textbooks like Genki will have you drill new conjugations with several words before moving on. (If you’d like even more drill practice with conjugations, I highly recommend this website.)
Drills can be useful, but ultimately you want to use adjectives in the context of conversation and understanding Japanese.
There are many ways to better immerse yourself in Japanese, and natural uses of adjectives will inevitably come up, but if you want more tailored practice while getting corrections, there’s no better way to do so than by working with a Japanese tutor.
If you’d like to work with a tutor who can answer any questions you may still have about adjectives, or who can help you use them in a more instinctive way, take a look at our many 上手なチューター (jouzu na chu-ta- = skilled tutors) over on Wyzant! We’d be happy to help you reach your Japanese goals.
