Adjectives are words that describe nouns and pronouns by showing that they have a certain quality; adjectives tell what kind. In Japanese they can either come directly before a noun, as in English, or after a particle.

大きい犬です。(This is) a big dog.
この犬は大きいです。This dog is big.

The two types of Japanese adjectives

Japanese has two main categories of adjective, the い and な adjective. They do not carry different nuances but do get conjugated in different ways.

新しい(あたらし>・ new)簡単な (かんたん・simple
古い(ふる・old)複雑な (ふくざつ>・complicated)
大きい (おおき・big)大切な (大切・important)
小さい (ちいさ・small)特別な (とくべつ・especial)
美味しい (おいし・delicious)有名な (ゆうめい・famous)

い adjectives

The い of an い adjective is part of the word itself and is conjugated directly. The same pattern of conjugation is followed by all い adjectives and, although the conjugations in this chart are broken down for clarity, the highlighted endings can simply be pasted onto other い adjectives as is. Just like verbs, adjectives also have polite and casual forms.

  • Most forms involve replacing い with something else and this will be shown in bold.
  • One variant of the polite form is made by adding the copula です onto the plain form and this will be shown in blue.
  • To make negative forms of adjectives, ない is added onto the く form of an adjective. This will be shown in orange.
Plain non-past小さ大き
Plain past小さかった大きかった
Plain negative小さない大きない
Plain negative past小さなかった大きなかった
Polite non-past小さいです大きいです
Polite past小さかったです大きかったです
Polite negative 1小さありません大きありません
Polite negative 2小さないです大きないです
Polite negative past 1小さありませんでした大きありません
Polite negative past 2小さなかったです大きなかったです

Both of the listed polite negative forms are very similar. The first variant is slightly more formal, the second is slightly more colloquial.

この家は大きいです。This is a big house.
彼女の鼻がとても小さかったです。Her nose was very small.

な adjectives

This type of adjective is a little bit more complicated. The な of a な adjective is not actually part of the word, like the い of an い adjective is, but is rather the second of Japanese’s three copulas. (The first one is だ・です, which we learned about on page 4).

Unlike い adjectives, a な adjective itself does not conjugate. Depending on its place in the sentence a な adjective will take either the copula な or the copula だ and this copula is conjugated to show whether the verb is positive/negative or past/non-past

  • • な is an attributive copula; when a な adjective comes directly before the noun it modifies a conjugation of な is added onto the adjective. な connects adjectives and nouns.
  • • だ is a predicative copula; when a な adjective ends a sentence, a conjugation of だ (not な) is used.
Form/ConjugationThe copula なThe copula だ
Plain pastだっただった
Plain negativeでない(では・じゃ)ない
Plain negative pastでなかった(では・じゃ)なかった
Polite non-pastN/Aです
Polite pastN/Aでした
Polite negative 1N/A(では・じゃ)ありません
Polite negative 2N/A(では・じゃ)ないです
Polite negative past 1N/A(では・じゃ)なかったです
Polite negative past 2N/A(では・じゃ)ありませんでした

Just as with い adjectives, the variant 1 is slightly more formal and variant 2 is slightly more colloquial. Similarly, じゃ and では serve the same function. じゃ is a contraction of では and is often used in speech, whereas では is more commonly used in writing.

In the below examples, notice how な or だ is used depending on whether the adjective comes before or after the noun it modifies.

この人は有名。This person is famous.
これは有名人だ。This is a famous person

このファイルは大切ではない。This file is not important.
これは大切でないファイルだ。This is a not-important file

It is common (and much simpler) to use な to connect an adjective to a noun and then conjugate だ・です, rather than な, to show whether the statement is positive/negative or past/non-past.

これは大切ファイルではない(です)。This is not an important file.