Meaning
We learnt “きれい“（this） here. This is called “な形容詞”(Na-adjective). In Japanese there are two types of adjectives, Na-adjective and “い形容詞”(I-adjective). English adjectives don’t conjugate but Japanese adjectives conjugate when they modify nouns. Let’s take a look.
Na-adjective
This adjective finishes “な“（na）when modifies noun.
・この 花 は きれい です。(This flower is beautiful.)
Let’s change this sentence and make the adjective modify the “flower”
・これ は きれいな 花 です。（This is a beautiful flower.)
“きれい“ conjugated to “きれいな“, the adjective finishes “な“ before the noun, so we call them “な形容詞”(Na-adjective).
I-adjective
This adjective finished “い“（i） when it modifies noun.
・あの山は高いです。（That mountain is high.)
Let’s change this sentence and make the adjective modify the “flower”
・あれは高い山です。（That is a high mountain.)
I-adjectives do not change when they directly modify a noun.
（However, they do conjugate in negative and past forms.）
But the adjective finishes “い“before the noun, so we call them “い形容詞“（I-adjective)
Negative Sentence
“な形容詞“（Na-adjective)
This would be the same as “〜は〜です”. You just have to change “です” into “ではないです“
・この花はきれいではないです。
“い形容詞“（I-adjective)
The adjective will conjugate, and “い” will be “くない”.
・あの山は高いです。（That mountain is high.)
・あの山は高くないです。（That mountain isn’t high.)
・この花は美しいです。（This flower is beautiful.)
・この花は美しくないです。（This flower isn’t beautiful.)
Question sentence
This would be very easy. Just add “か“ as the same as “〜は〜です”.
・あの山は高いですか。（Is that mountain high?)
ーいいえ、高くないです。（No, that isn’t high.)
・その花はきれいですか。（Is that flower beautiful?)
ーいいえ、きれいではないです。（No, that isn’t beautiful.)
Adverb
This is simple as it is the same as English. You can just add adverb before the adjective.
・あの山は少し高いです。（That mountain is a little bit high.)
・この花はとてもきれいです（This flower is very beautiful.)
Vocabulary list
| Na-adjective | ||
| きれい | kirei | beautiful/clean |
| けんこう（健康） | kenkō | healthy |
| I-adjective | ||
| たかい（高い） | takai | high/expensive |
| うつくしい（美しい） | utsukushī | beautiful |
| やさしい（優しい） | yasashī | kind |
| むずかしい（難しい） | muzukashī | difficult |
| おもしろい（面白い） | omoshiroi | interesting/funny |
| Adverb | ||
| とても | totemo | very |
| ほんとう（本当）に | hontōni | really |
| あまり(only used with negative sentence) | amari | not that much |
| Others | ||
| いわ（岩） | iwa | rock |
| いし（石） | ishi | stone |
| やま（山） | yama | mountain |
| はな（花） | hana | flower |
| かみのけ（髪の毛） | kaminoke | hair |
| モデル | moderu | model |
Example
・わたしの母は健康です。（My mother is healthy)
(Watashi no haha wa kenkō desu.）
・あのモデルはとても美しいです。(That model is very beautiful.)
(Ano moderu wa totemo utsukushii desu.)
・そのスマホは高いですか？（Is that smartphone expensive?)
(Sono sumaho wa takai desuka?)
・いいえ、あまり高くないです。（No, it isn’t that expensive.)
(Iie, amari takakunai desu.)
・太郎の彼女は優しいですか？（Is Taro’s girlfriend kind?)
(Tarō no kanojo wa yasashī desu ka?)
・はい、優しいです。（Yes, she is kind.)
(Hai, yasashī desu.)
・日本語は本当に難しいです。（Japanese is really difficult.)
(Nihongo wa hontōni muzukashī desu.)
Practice Section
Exercise 1: Translate to Japanese
1. He is very kind.
2. Is that book interesting?
3. No, this isn’t that interesting.
Exercise 2: Translate to English
1. かれの家は大きいですか？
2. はい、とても大きいです。
3. わたしの髪の毛は長いです。
Answers are at the end.
Special Words That Look Like Na-Adjectives
Before we look at summary, here are a few special words that look like Na-adjectives:
・大きな
・小さな
・いろんな
・おかしな
These words only appear before nouns. They do not conjugate like regular adjectives.
There are a few special words like 大きな and 小さな that only appear before nouns. Just memorize them.
For example:
・これは大きな岩です。
・あれは小さな石です。
Even Japanese people rarely think about the difference — we just use them naturally. So don’t worry too much. Just remember that they only come before nouns.
Summary
There are two types of adjectives in Japanese: な-adjectives and い-adjectives.
• な-adjectives add な before a noun (きれい → きれいな花).
• い-adjectives stay the same when modifying a noun (大きい → 大きい岩).
• For negative sentences, な-adjectives change like “〜は〜です” (きれいです → きれいではないです).
• い-adjectives change い → くない in negative form (高い → 高くない).
• To make a question, simply add か at the end of the sentence.
• Some special words like 大きな, 小さな, いろんな, and おかしな only appear before nouns. Just memorize them.
Answer
Exercise 1: Translate to Japanese
1. He is very kind. → かれはとても優しいです。
2. Is that book interesting? → その本は面白いですか？
3. -No, this isn’t that interesting. →いいえ、この本はあまり面白くないです。
※(3) is an answer to (2). Since (3) says “this”, the book is near the (3)‘s speaker. That means, “that” in (2) sentence should be translated “その” rather than “あの“→ I have explained this here.（Internal link)
Exercise 2: Translate to English
1. かれの家は大きいですか？→ Is his house big?
2. はい、とても大きいです。→ Yes, it is very big.
3. わたしの髪の毛は長いです。→ My hair is long.
Next we will learn particle!