I Adjectives vs Na Adjectives: How to Tell Them Apart
I adjectives vs na adjectives is the first big split in Japanese adjectives. I adjectives end in い (i) and change their own ending to make the negative and the past. Na adjectives take な (na) before a noun and never change themselves. Instead, the word after them changes. So たかい (takai, tall or expensive) becomes たかくないです (takakunai desu, is not tall), while しずか (shizuka, quiet) becomes しずかじゃありません (shizuka ja arimasen, is not quiet).
How do you tell i adjectives from na adjectives?
Look at the dictionary form. Most i adjectives end in -ai, -ii, -ui or -oi, written with a hiragana い at the end. Na adjectives usually end in another sound, such as しずか (shizuka) or げんき (genki, well, lively). Dictionaries and word lists often mark them, and many learners write them with な to remember: しずかな.
Here are eight beginner adjectives that appear on most JLPT N5 word lists.
| I adjectives | Na adjectives |
|---|---|
| たかい (takai, tall, expensive) | しずか (shizuka, quiet) |
| やすい (yasui, cheap) | げんき (genki, well, lively) |
| おおきい (ōkii, big) | きれい (kirei, pretty, clean) |
| いい (ii, good) | ゆうめい (yūmei, famous) |
Which na adjectives end in i?
A few common na adjectives end in i, and they catch almost every beginner.
- きれい (kirei, pretty, clean). The い is part of the word, not an ending. A useful hint: adjectives ending in -ei are almost always na adjectives.
- ゆうめい (yūmei, famous). Another -ei word, so it is a na adjective too.
- きらい (kirai, disliked). This one ends in -ai, so it looks like an i adjective, but it is a na adjective. The same goes for すき (suki, liked).
So you say きれいじゃありません (kirei ja arimasen, is not pretty), never きれくない. There is one more trap on the i adjective side. いい (ii, good) changes from its older form よい (yoi), so the negative is よくないです (yokunai desu) and the past is よかったです (yokatta desu).
How do i and na adjectives go before a noun?
An i adjective goes straight before the noun: たかい やま (takai yama, a tall mountain). A na adjective needs な in between: しずかな まち (shizuka na machi, a quiet town), ゆうめいな ひと (yūmei na hito, a famous person).
At the end of a sentence, both simply take です (desu) in polite speech: やまは たかいです (yama wa takai desu, the mountain is tall) and まちは しずかです (machi wa shizuka desu, the town is quiet). The な disappears here. If the は looks odd, our guide to wa vs ga explains it.
How do you conjugate i adjectives and na adjectives?
Start with the polite forms. For an i adjective, drop the final い and add the new ending.
| たかい (takai) | Polite | Plain |
|---|---|---|
| Present | たかいです (takai desu) | たかい (takai) |
| Negative | たかくないです (takakunai desu) or たかくありません (takaku arimasen) | たかくない (takakunai) |
| Past | たかかったです (takakatta desu) | たかかった (takakatta) |
| Past negative | たかくなかったです (takakunakatta desu) | たかくなかった (takakunakatta) |
For a na adjective, the word stays the same and only the part after it changes.
| しずか (shizuka) | Polite | Plain |
|---|---|---|
| Present | しずかです (shizuka desu) | しずかだ (shizuka da) |
| Negative | しずかじゃありません (shizuka ja arimasen) or しずかではありません (shizuka de wa arimasen) | しずかじゃない (shizuka ja nai) |
| Past | しずかでした (shizuka deshita) | しずかだった (shizuka datta) |
| Past negative | しずかじゃありませんでした (shizuka ja arimasen deshita) | しずかじゃなかった (shizuka ja nakatta) |
One common mistake: i adjectives never take でした. The past of たかい is たかかったです, not たかいでした. Plain forms are for friends and family, so polite forms are the safer place to begin. For verbs in the past, see our guide to the Japanese past tense.
When you learn a new adjective, learn its type with it. Our JLPT N5 vocabulary list is a good place to collect the rest.
How LanguaCards helps
LanguaCards has Japanese flashcards for every JLPT level from N5 to N1, each with audio and romaji, so you can hear たかい and しずか as you learn them. Reviews bring each adjective back before you would forget it, which makes the two types easier to keep apart.