い-Adjectives and Colors
Japanese adjectives do something English ones never do: they conjugate. In this chapter you'll bend い-adjectives like 高い through present, past and negative forms, tame the one irregular いい, and paint your sentences with colour.
Adjectives that carry their own tense
An い-adjective is an adjective whose dictionary form ends in the kana い: 高い (expensive, high), 大きい (big), 寒い (cold). In English, tense lives in the verb — "it is cold", "it was cold". In Japanese, the adjective itself changes: 寒い becomes 寒かった for "was cold". No extra verb needed.
That final い is the moving part — it swaps out for the negative and past endings, while everything before it stays put. Learn one small set of endings and you can conjugate every い-adjective in the language (with exactly one exception, which gets its own section below).
Watch out: not everything ending in い belongs to this family. きれい (pretty) and きらい (disliked) end in い but are な-adjectives, which follow different rules and have their own chapter.
Listen: い-adjectives on the street
Kyle and Meera describe things with い-adjectives. Tap ► to hear the conjugations in real speech.
Kyleやっと昼ご飯の時間ですね。
yatto hirugohan no jikan desu ne.
It's lunch time, finally!
Meeraハンバーガーはどうですか？
hanbagā wa dō desu ka?
What about a hamburger?
Kyleううん、食堂は遠いですよ
ūn, shokudō wa tōi desu yo
No, the canteen is far
Meeraコンビニのカレーパンはどうですか？
konbini no karē pan wa dō desu ka?
What about a curry bread at the convenience store?
Listen: negative い-adjectives at the zoo
〜くない in conversation — how the negative really sounds.
Muriここの鳥は多くないですか？
koko no tori ha ōkunai desu ka?
There aren't many birds here?
Yaya確かにちょっと少ないですね
tashika ni chotto sukunai desu ne
There are few of them, indeed
Muriでも昨日より多いですね
demo kinō yori ōi desu ne
But more than yesterday
Yayaそうですか？
sō desu ka?
Is that so?
Two jobs: before a noun, or before です
い-adjectives slot into sentences in two ways. Directly before a noun, with nothing in between: 高いかばん (an expensive bag) — no の, no な. Or at the end of the sentence as the predicate, with です added purely for politeness: かばんは高いです (the bag is expensive).
That です is just a politeness marker here — it never changes form after an い-adjective, no matter the tense. Keep that in mind for the conjugation sections below.
これは新しい車です。
kore wa atarashii kuruma desu.
This is a new car.
Adjective straight onto the noun: 新しい + 車.
この車は速いです。
kono kuruma wa hayai desu.
This car is fast.
Same adjective family, now working as the predicate.
今日は暑いです。
kyō wa atsui desu.
It is hot today.
Weather sentences need no subject — the topic 今日 is enough.
小さい猫はかわいいです。
chiisai neko wa kawaii desu.
Small cats are cute.
Two い-adjectives in one sentence — one before the noun, one as the predicate.
Negative: 〜くない
To say something is not expensive, drop the final い and add くない: 高い → 高くない. In polite speech, just add です: 高くないです. You'll also meet the slightly more formal 高くありません — both forms appear on the JLPT N5 and mean exactly the same thing.
Never use じゃありません here — that negation belongs to nouns and な-adjectives, not to the い family.
このシャツは安くないです。
kono shatsu wa yasukunai desu.
This shirt is not cheap.
今日は寒くないです。
kyō wa samukunai desu.
It is not cold today.
この本は難しくありません。
kono hon wa muzukashiku arimasen.
This book is not difficult.
〜くありません — same meaning as 〜くないです, a touch more formal.
Past and past negative — the full table
For the past, drop the final い and add かった: 高かった (was expensive). The past negative builds on the negative form — 高くない loses its final い and gains かった too: 高くなかった (was not expensive). That completes all four forms:
| Non-past | Past | |
|---|---|---|
| Affirmative | 高い（です） | 高かった（です） |
| Negative | 高くない（です） | 高くなかった（です） |
The most common beginner mistake: never say 高いでした. The adjective carries the tense; です stays です in every cell of the table.
昨日は暑かったです。
kinō wa atsukatta desu.
It was hot yesterday.
テストは難しくなかったです。
tesuto wa muzukashikunakatta desu.
The test was not difficult.
Long, but regular: 難しい → 難しくない → 難しくなかった.
古いかばんは重かったです。
furui kaban wa omokatta desu.
The old bag was heavy.
The one irregular: いい
いい (good) is the single irregular い-adjective. It descends from the older form よい, and every conjugated form still uses that よ: negative よくない, past よかった, past negative よくなかった. Only the plain non-past keeps the modern いい — there is no いくない and no いかった.
You'll hear よかった constantly as a stand-alone phrase meaning "Thank goodness!" or "I'm glad".
天気はとてもよかったです。
tenki wa totemo yokatta desu.
The weather was very good.
このレストランはよくないです。
kono resutoran wa yokunai desu.
This restaurant is not good.
昨日の映画はよくなかったです。
kinō no eiga wa yokunakatta desu.
Yesterday's film was not good.
Colours: nouns first, い-adjectives second
Here's a surprise: Japanese colour words are nouns. 赤 is "the colour red", 緑 is "the colour green". As nouns, they connect to other nouns with の — 緑のシャツ (a green shirt) — and they sit happily before です: シャツは緑です。
Six colours, however, also come with a true い-adjective form, which slots directly onto a noun and conjugates like everything in this chapter:
| Colour | Noun | い-adjective |
|---|---|---|
| red | 赤 | 赤い |
| blue | 青 | 青い |
| white | 白 | 白い |
| black | 黒 | 黒い |
| brown | 茶色 | 茶色い |
| yellow | 黄色 | 黄色い |
So "a red shirt" is 赤いシャツ, but "a green shirt" must be 緑のシャツ — 緑, 紫, ピンク, オレンジ, グレー, 金 and 銀 have no い form at all. There is no such word as 緑い.
To ask what colour something is, use 何色 (what colour): そのシャツは何色ですか。 — "What colour is that shirt?"
More practice in the game
Six free browser lessons with native audio drill this chapter end to end: い-adjectives on the street, all three conjugated forms at the zoo, and describing clothes and colours in the shop.
Chapter vocabulary
All thirteen colour words from the game, followed by ten い-adjectives you can now conjugate through every form.
Tap ► to hear the native audio from the game, or tap a word to open its dictionary entry.
Why green traffic lights are "blue"
Historically, 青 covered the whole blue–green range, and 緑 only became an everyday colour word relatively recently. The old, wider meaning survives in modern set phrases: the green traffic light is officially the 青信号 ("blue signal"), a green apple is a 青りんご, and fresh green leaves are 青葉. Japan has even leaned into the name — traffic lights there use the bluest shade of green international rules allow. So when someone says the light is 青, look for green.
Test yourself
Eight questions to bend い-adjectives through every form — and keep your colours straight.
8 quick questions on this chapter.
Your score
Common questions
Quick answers about this chapter's grammar.
Why does いい become よくない instead of いくない?
いい descends from the older adjective よい, and every conjugated form is still built on that よ: よくない, よかった, よくなかった. Only the plain non-past modernised to いい. Memorise the three よ-forms and you've handled the only irregular い-adjective in the language. Bonus: よかった on its own is a set phrase meaning "Thank goodness!"
Do I still need です after an い-adjective?
In polite speech, yes — but it is purely a politeness marker. Unlike with nouns, this です never changes: tense and negation live inside the adjective itself. So "was expensive" is 高かったです, never 高いでした, and "is not expensive" is 高くないです, never 高いじゃありません.
Is きれい an い-adjective?
No — and it's the most common trap at N5. きれい (pretty, clean) and きらい (disliked) end in い but are な-adjectives: before a noun they take な (きれいなシャツ), and their negative is きれいじゃありません, never きれくない. When in doubt, check how the word negates.
What is the difference between <ruby>赤<rt>あか</rt></ruby> and <ruby>赤<rt>あか</rt></ruby>い?
赤 is a noun — the colour red itself — while 赤い is the adjective "red". Before a noun, both work but connect differently: 赤いシャツ (adjective, nothing in between) or 赤のシャツ (noun + の). For colours without an い form, like 緑 or ピンク, the noun + の pattern is your only option.
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