Japanese Adjectives: い and な
Japanese adjectives are divided into two types, and this is more important than it seems: い-adjectives (たかい takai — expensive) change themselves, while な-adjectives (きれいな kirei-na — beautiful) behave like nouns and require a copula. Negation and past tense are formed differently for each.
A Japanese adjective can do something a Russian one cannot: conjugate through tenses without any verb. 'It was expensive' is one word: たかかった. Two types, two sets of rules — and the whole description of the world is in your hands.
What kinds of adjectives are there in Japanese?
| Type | Example | Negation | Past |
|---|---|---|---|
| い-adjective | たかい (expensive) | たかくない | たかかった |
| な-adjective | きれい (beautiful) | きれいじゃない | きれいだった |
How to conjugate い-adjectives
- Drop the final い and add endings: たか-.
- Negation: -くない → たかくない (not expensive).
- Past: -かった → たかかった (was expensive).
- Before a noun it is used as is: たかい本 (expensive book).
- Exception: いい (good) changes from the form よい — よくない, よかった.
How to say 'not expensive' and 'was expensive'
For い-adjectives, the ending itself changes: たかい → たかくない (not expensive) → たかかった (was expensive). Russian speakers habitually put the negation before the word — in Japanese it is built into the ending.
How な-adjectives work
They are closer to nouns. Before a noun they add な: きれいな花 (beautiful flower). At the end of a sentence they rely on です/だ: 花はきれいです. Past and negation are taken from the copula: きれいでした, きれいじゃない.
Why きれい is not an い-adjective
The word ends in い, but that is part of the root, not a sign of type: きれい behaves as a な-adjective (きれいな花). The same trap catches 有名 (famous) and 嫌い (unpleasant) — they are memorized separately.
FAQ
- How to distinguish い- from な-adjectives?
- い-adjectives end in い and change themselves (たかい → たかかった). な-adjectives require な before a noun (きれいな) and rely on the copula です/だ. Caution: there are words ending in い that are actually な-type (e.g., きれい).
- Is it true that an adjective changes by tense without a verb?
- Yes, for い-adjectives. 'It was expensive' — たかかった, without an auxiliary verb. This is a feature of Japanese that you quickly get used to.
- Why does いい behave strangely?
- いい (good) is an exception: its forms are taken from the old stem よい. Therefore 'not good' is よくない, 'was good' is よかった, not 'いくない'.
- Where to place an adjective in a sentence?
- Before the noun it describes: たかい本 (expensive book), きれいな花 (beautiful flower). The order is like in Russian — the modifier before the word.
Updated: 2026-06-25