Japanese Grammar Fundamentals: Introduction to Adjectives

Adjectives are words that describe the properties of nouns. These can include general descriptors such as numbers (five cats, 五匹ごひきの猫ねこ [go-hiki no neko]), colors (blue flowers, 青あおい花はな [aoi hana]), or other qualities that help provide more information about the item which is being described.

Japanese has two primary groups of adjectives: I-adjectives and NA-adjectives. Let’s take a quick look at both.

Identifying an Adjective’s Type

To determine if an adjective is really an I-adjective, the most reliable way is to look at how it is written in kanji.

I-adjectives will always have okurigana ¹: 〜い (-i) in most cases, though 〜しい (-shii) is also common for adjectives with emotional connotations and 〜ない (-nai) appears occasionally as well. Examples include:
- 良いい (ii, good)
- 悪わるい (warui, bad)
- 嬉うれしい (ureshii, happy)
- 美うつくしい (utsukushii, beautiful)
- 少すくない (sukunai, scarce)
- 危あぶない (abunai, dangerous)
NA-adjectives often do not have okurigana. When they do, however, it is most often one of 〜か (-ka), 〜やか (-yaka), or 〜らか (-raka) due to reasons stemming from Classical Japanese². No NA-adjective ending in い (i) has okurigana, however, as demonstrated³ in the following examples:
- 綺麗きれい (kirei, neat/pretty)
- 無礼ぶれい (burei, rude/impolite)
- 自然しぜん (shizen, natural)
- 静しずか (shizuka, quiet)
- 明あきらか (akiraka, clear/unambiguous)
- 安やすらか (yasuraka, peaceful)
- 速すみやか (sumiyaka, prompt/speedy)

い (I) Adjectives

I-adjectives take their name from the fact that, without exception, they all end in the syllable い (i). That said, as we demonstrated above, not all adjectives that end in い (i) are in this group.

In practice, I-adjectives behave in a similar manner to verbs. They can accept many of the same endings⁴, and in casual speech they even replace the be-verb だ・です (da/desu) at the end of declarative sentences.

For example, if you just tried some takoyaki⁵ and loved the taste of it, you might exclaim the following:

Formal	Informal
このたこ焼やきは美味おいしいです！ Kono takoyaki wa oishii desu! This takoyaki is delicious!	このたこ焼やきは美味おいしい！ Kono takoyaki wa oishii! This takoyaki is delicious!

Using I-Adjectives

When adjectives appear directly beside a noun, Japanese grammar places the adjective first (as it works in English). In the case of I-adjectives, you just place them right next to each other:

adjective + noun

青あおい空そら (aoi sora, blue sky)
高たかいビル (takai biru, tall building)
速はやい電車でんしゃ (hayai densha, fast train)

Similar to English, it is also possible to move the adjective to the predicate (second half of the sentence), where it describes the noun subject of the sentence. This typically takes the format:

subject/noun + は + adjective + です⁶

あの空そらは青あおいです。 (Ano sora wa aoi desu. “That sky is blue.”)
このビルは高たかい！ (Kono biru wa takai! “This building is tall!”)
この電車でんしゃは速はやいですか？ (Kono densha wa hayai desu ka? “Is this train fast?”)

な (NA) Adjectives

NA-adjectives derive their name from the fact that when used immediately before a noun you are supposed to add the particle な (na)⁷: 綺麗きれいな人ひと (kirei na hito, beautiful person)

Whereas I-adjectives behave like verbs, NA-adjectives behave like nouns. だ・です (Da/desu) is always required when a NA-adjective appears at the end of a sentence, even in informal speech, since the adjective is unable to accept endings on its own. Consider the following examples:

Present Tense	Past Tense
ここは危険きけんです。 Koko wa kiken desu. It is dangerous here.	ここは危険きけんでした。 Koko wa kiken deshita. It was dangerous here.

Using NA-Adjectives

As we mentioned earlier, the defining feature of NA-adjectives is the use of the particle な between an adjective and its associated noun when the two are placed adjacent to each other:

adjective + な + noun

特別とくべつなレッスン (tokubetsu na ressun, special lesson)
妙みょうな匂におい (myou na nioi, strange smell)
自然しぜんなやり方かた (shizen na yarikata, natural way of doing things)

There are many cases where NA-adjectives form the base for compound words. In these cases, the な (na) is typically omitted.

As with I-adjectives, it is also possible to move the adjective to the predicate (second half of the sentence), where it describes the noun subject of the sentence. The format remains unchanged in this case, except that だ (da) is added to the end of the sentence in informal speech⁸:

subject/noun + は + adjective + だ・です

あの空そらは青あおいです。 (Ano sora wa aoi desu. “That sky is blue.”)
このビルは高たかい！ (Kono biru wa takai! “This building is tall!”)
この電車でんしゃは速はやいですか？ (Kono densha wa hayai desu ka? “Is this train fast?”)

の (NO) Adjectives

NO-adjectives are a lesser (and somewhat contested) classification of adjectives in Japanese which function very similarly to NA-adjectives, except that where NA-adjectives would use the particle な (na) before a noun, NO-adjectives use の (no) instead.

The reason for the change in particle (and why some people don’t consider these true adjectives) is that NO-adjectives are nouns which have been repurposed to function as adjectives.

For example, many colors (any that end in 〜色いろ [iro]), the word refers to the color itself. Let’s perform a quick comparison between the colors brown (茶色ちゃいろ chairo) and blue (青あおい aoi) to help demonstrate the way they behave differently.⁹

Used as an Adjective	Used as a Noun
あの茶色ちゃいろの本ほんはすごく楽たのしい。 Ano chairo no hon wa sugoku tanoshii. That brown book is very entertaining.	茶色ちゃいろが好すきですか？ Chairo ga suki desu ka? Do you like [the color] brown?
あの青あおいの本ほんはすごく楽たのしい。 Ano aoi hon wa sugoku tanoshii. That blue book is very entertaining.	青あおが好すきですか？ Ao ga suki desu ka? Do you like [the color] blue?

In both examples, you’ll notice that 茶色ちゃいろ (chairo, brown) remained unchanged, other than that we added の (no) when it was placed right before a noun.

青あおい (aoi, blue), on the other hand, is an I-adjective. To use it as a noun, we need to do something about the ending. For colors, it’s a simple as dropping the 〜い (-i) at the end. For other I-adjectives we may need to replace 〜い (-i) with another ending (typically either 〜さ [-sa] or 〜み [-mi])¹⁰.

The Placeholder Pronoun の (No)

Pronouns are words that are used in place of nouns to avoid having to awkwardly repeat full names or specifics. の (No) is used in place of a noun to refer to an object previously mentioned in the conversation.

For example, let’s look at a hypothetical conversation between two people who are out clothes shopping:

どのスカートが欲ほしい？
Dono sukaato ga hoshii?
Which skirt do you want?

その青あおいの。
Sono aoi no.
That blue one.

The first person is asking which item the second person wants (in this case, from a selection of skirts they’ve been looking at). Since we’ve already established that we’re talking about skirts, the second person uses の (no) in place of スカート (sukaato) when answering the question.

Bonus topic: Colors!

This has been quite a busy lesson so far! Let’s review the most commonly-used colors quickly to provide some adjectives to start practicing with.

青あおい (aoi) I-adjective blue
赤あかい (akai) I-adjective red
茶色ちゃいろ (chairo) NO-adjective brown
黄色きいろ (kiiro) NO-adjective yellow
桃色ももいろ (momoiro) NO-adjective pink
黒くろい (kuroi) I-adjective black
白しろい (shiroi) I-adjective white
オレンジ (orenji) NO-adjective orange
灰色はいいろ・鼠色ねずみいろ (haiiro/nezumi iro) NO-adjective gray

Are there any adjectives you’d like to know how to say in Japanese? Ask in the comments!

Vocabulary

In order of appearance. Words that only appear in footnotes are at the end of the list.

五ご (go) five
〜匹ひき (-hiki) counter for four-legged animals (is attached to the number of animals being counted)
猫ねこ (neko) cat
青あおい (aoi) blue
花はな (hana) flower
送おくり仮名がな (okurigana) Kana that are added to kanji characters to help form words. Often added to provide the endings for verbs or adjectives.
良いい (ii) good
悪わるい (warui) bad
嬉うれしい (ureshii) happy
美うつくしい (utsukushii) beautiful
少すくない (sukunai) few
危あぶない (abunai) dangerous
綺麗きれい (kirei) neat, pretty, beautiful, clean
無礼ぶれい (burei) rude, impolite
自然しぜん (shizen) natural (e.g. behavior)
静しずか (shizuka) quiet
明あきらか (akiraka) clear, unambiguous
安やすらか (yasuraka) peaceful
速すみやか (sumiyaka) prompt, speedy
だ (da) casual form of です (to be)
です (desu) to be
たこ焼やき (takoyaki) octopus balls
美味おいしい (oishii) tasty, delicious
空そら (sora) sky
高たかい (takai) high, tall, expensive
ビル (biru) building
速はやい (hayai) fast, quick
電車でんしゃ (densha) [electric] train
人ひと (hito) person
ここ (koko) here
危険きけん (kiken) dangerous
特別とくべつ (tokubetsu) special
レッスン (ressun) lesson
妙みょう (myou) strange
匂におい (nioi) smell, scent
やり方かた (yarikata) way of doing something
色いろ (iro) color
茶色ちゃいろ (chairo) brown (literally, “tea color”)
本ほん (hon) book
すごい (sugoi) great, amazing
楽たのしい (tanoshii) entertaining, fun
スカート (sukaato) skirt
欲ほしい (hoshii) desired
赤あかい (akai) red
黄色きいろ (kiiro) yellow (literally, “yellow color”)
桃色ももいろ (momoiro) pink (literally, “peach color”)
黒くろい (kuroi) black
白しろい (shiroi) white
オレンジ (orenji) orange
灰色はいいろ (haiiro) gray (literally, “ash color”)
鼠色ねずみいろ (nezumi iro) gray (literally, “mouse color”)
面白おもしろい (omoshiroi) amusing, entertaining
暖あたたかい (atatakai) warm

Thanks!

Thanks for checking out our introduction to Japanese adjectives! If this is your first time visiting the site, you can check out the first lesson in our Japanese Grammar Fundamentals series here.

As always, if you have any suggestions on how to improve things or topics you would like to see us cover, feel free to drop a note in the comments!

Next week we’re going to do a formal introduction to Japanese verbs, allowing you to start unlocking the full potential of the language. See you then!

Extra kana surrounding the kanji, most often at the end of a word, often for purposes of adding endings to words
A topic for a later post
To the extent one can prove a negative
We will address adjective endings alongside verb endings as we introduce them in later lessons
Octopus balls! Read more on Wikipedia
Remember, leave です off in casual speech
Etymologically, this な (na) is derived from Classical Japanese なり (nari), which is an archaic form of だ・です (da/desu). The closest analogue, if you were to try and translate it literally, would be to the effect of “the noun which is adjective“
There are some nuances to this which shall be addressed in later lessons as they arise.
I’m having trouble coming up with a good NA-adjective to use in this comparison, but if someone has an example, feel free to drop it in the comments!
Per DAIJIRIN, 〜さ (-sa) is for when something you’re talking about a state, condition, or something that can be measured. 〜み (-mi) refers to a state or condition resembling that which the adjective describes.

For example, 面白おもしろい (omoshiroi) means “fun/amusing”, while 面白おもしろさ (omoshirosa) refers to the degree to which something is entertaining. 暖あたたかい (atatakai) means “warm”, while 暖あたたかみ (atatakami) refers to warmth in an abstract sense.

Kanji Usage Data
Jouyou	五、人、仮、別、匂、匹、危、名、味、好、妙、安、少、悪、方、明、暖、本、桃、楽、欲、灰、無、然、焼、特、猫、白、礼、空、美、自、良、色、花、茶、赤、車、送、速、険、電、青、静、面、高、麗、黄、黒
Jinmei-You	嬉、綺
Hyougaiji	鼠