N5Chapter 14

Adjectives Part 1: い-Adjectives

Learning objectives

  • Identify い-Adjectives and distinguish them from other word groups.
  • Conjugate い-Adjectives into present, past, and negative forms.
  • Use adjectives to modify nouns directly.
  • Appreciate the cultural connection between adjectives and the four seasons.
N5 context

In Japanese, adjectives are more than just describing words—they are like mini-verbs! They can change their endings to show if something is hot, was hot, or is not hot. There are two main groups of adjectives, and today we are focusing on the first group: い-Adjectives (i-adjectives). These words always end in the hiragana character い and are incredibly versatile.

Anime illustration of Susu holding a huge watermelon tagged おおきい and a tiny strawberry tagged ちいさい.

1. What are い-Adjectives?

い-adjectives normally end in the hiragana い and conjugate by changing that ending. However, not every word ending in い is an い-adjective: common な-adjectives such as きれい and ゆうめい must be learned separately. Japanese adjectives do not literally contain “is”; rather, い-adjectives can form a plain predicate without a copula.

Vocabulary語彙
6 terms

  • たかい

    い-Adj

    takai

    Expensive / Tall

  • やすい

    い-Adj

    yasui

    Cheap

  • おいしい

    い-Adj

    oishii

    Delicious

  • あつい

    い-Adj

    atsui

    Hot

  • さむい

    い-Adj

    samui

    Cold

  • おもしろい

    い-Adj

    omoshiroi

    Interesting

この すし は おいしい です。

Kono sushi wa oishii desu.

This sushi is delicious.

あの ビル は たかい です。

Ano biru wa takai desu.

That building over there is tall.

きょう は あつい です ね。

Kyou wa atsui desu ne.

It's hot today, isn't it?

2. Conjugating い-Adjectives

Unlike nouns, you change the adjective itself to show tense. To conjugate, you drop the final い and add a new ending.

Conjugation活用

たかい — い-adjective tenses

FormJapaneseMeaningActions
Present Affirmative · 〜いたかい ですtakai desuIs expensive
Present Negative · 〜くないたかくない ですtakakunai desuIs not expensive
Past Affirmative · 〜かったたかかった ですtakakatta desuWas expensive
Past Negative · 〜くなかったたかくなかった ですtakakunakatta desuWas not expensive
Grammar文法
[Adjective Root] ＋ [Ending]

means Conjugating for tense and negativity.

Formation

Drop the final 'i' and attach the appropriate suffix.

Examples

きのう は さむかった です。

Kinou wa samukatta desu.

Yesterday was cold.

この ほん は おもしろくない です。

Kono hon wa omoshirokunai desu.

This book is not interesting.

テスト は むずかしくなかった です。

Tesuto wa muzukashikunakatta desu.

The test was not difficult.

あさごはん は やすかった です。

Asagohan wa yasukatta desu.

Breakfast was cheap.

えいが は おもしろかった です か。

Eiga wa omoshirokatta desu ka.

Was the movie interesting?

コーヒー は つめたくない です。

Koohii wa tsumetakunai desu.

The coffee is not cold.

3. Direct Noun Modification

To describe a noun directly (e.g., “A delicious apple”), you simply place the adjective in its dictionary form directly before the noun. No particle is needed!

Grammar文法
[い-Adjective] ＋ [Noun]

means Modifying a noun directly.

Formation

Dictionary form adjective + Noun.

Examples

おいしい りんご です。

Oishii ringo desu.

It is a delicious apple.

たかい とけい を かいました。

Takai tokei o kaimashita.

I bought an expensive watch.

あつい おちゃ を のみます。

Atsui ocha o nomimasu.

I drink hot tea.

おもしろい ほん を よみました。

Omoshiroi hon o yomimashita.

I read an interesting book.

さむい くに に いきます。

Samui kuni ni ikimasu.

I am going to a cold country.

やすい カメラ は どこ です か。

Yasui kamera wa doko desu ka.

Where is a cheap camera?
Culture文化

4. Cultural Note: The Four Seasons and Nature (四季)

Japanese culture has a profound appreciation for the four seasons (Shiki). This is reflected in the language, where many adjectives are used to describe the specific “feeling” of a season.

  • Haru (Spring): Associated with atatakai (warm) and utsukushii (beautiful) cherry blossoms.
  • Natsu (Summer): Described as atsui (hot) and mushi-atsui (humid). Summer is the time for nigiyaka (lively) festivals.
  • Aki (Autumn): Known for suzushii (cool) breezes and the kirei (beautiful) changing leaves.
  • Fuyu (Winter): Characterized as samui (cold) and shiroi (white) snow.
  • Kachou Fuugetsu (花鳥風月): A four-character idiom literally meaning “Flower, Bird, Wind, Moon.” It represents the traditional themes of natural beauty in Japanese aesthetics.

Conversation Practice

Anime illustration of Yumi asking おいしいですか over ramen, and Susu lifting noodles and answering とてもおいしいです.
Talking About Food会話
Alice

その ラーメン は おいしい です か。

Sono raamen wa oishii desu ka?

Is that ramen delicious?

Tanaka

はい、 とても おいしい です。 でも、 ちょっと あつい です。

Hai, totemo oishii desu. Demo, chotto atsui desu.

Yes, it's very delicious. But it's a bit hot.

Alice

たかい です か。

Takai desu ka?

Is it expensive?

Tanaka

いいえ、 やすかった です よ。 ８００えん です。

Iie, yasukatta desu yo. Happyaku-en desu.

No, it was cheap. It's 800 yen.
Last Weekend's Trip会話
Ken

きのう、 どこ へ いきました か。

Kinou, doko e ikimashita ka?

Where did you go yesterday?

Yumi

うみ へ いきました。 とても おもしろかった です！

Umi e ikimashita. Totemo omoshirokatta desu!

I went to the sea. It was very interesting!

Ken

てんき は よかった です か。

Tenki wa yokatta desu ka?

Was the weather good?

Yumi

はい、 さむくなかった です。

Hai, samukunakatta desu.

Yes, it wasn't cold.

Chapter Summary

Key takeawaysまとめ
  • 1い-adjectives normally end in hiragana い, but words such as きれい and ゆうめい are な-adjectives.
  • 2To conjugate, drop the final い and add: 〜くない (neg), 〜かった (past), or 〜くなかった (past neg).
  • 3Modify nouns directly by placing the adjective before the noun (e.g., おいしい すし).
  • 4Japanese culture values the specific descriptive qualities of each of the four seasons.
  • 5The word 'yoi' (good) is irregular; its root changes to 'yoku' in all forms except present affirmative.

Knowledge Check

Test your adjective conjugation skills!

Practice Quiz
1 / 20

Which of these is an い-Adjective?

Applied review

Use what you learned

Focus: い-adjective conjugation. Try the task before revealing the model.

Guided practice練習

Produce the Japanese sentence, then compare it with the model answer.

  1. 1.Say “Yesterday was not cold.”

Reading practice読解

い-adjective conjugation in context

N5 mini-reading

Target: 1 minute
昨日は 寒かったですが、今日は 暖かいです。
Study this passage
  1. How did the weather change?