重要 (juuyou) conjugation
important, essential
重要 (じゅうよう, juuyou) is a na-adjective. Na-adjectives behave like nouns. The word itself never changes — you conjugate だ/です after it, and you need な to put it in front of a noun.
Conjugation table
| Form | Plain (casual) | Polite (~です) | When you use it |
|---|---|---|---|
| Dictionary / plain | 重要だ juuyouda | 重要です juuyoudesu | The form you look up. Also the casual “is ~”. |
| Negative | 重要じゃない juuyoujanai | 重要じゃないです juuyoujanaidesu | “is not ~”. |
| Past | 重要だった juuyoudatta | 重要でした juuyoudeshita | “was ~”. |
| Past negative | 重要じゃなかった juuyoujanakatta | 重要じゃなかったです juuyoujanakattadesu | “was not ~”. |
| Te-form | 重要で juuyoude | — | Links to the next clause: “~ and …”. |
| Adverb | 重要に juuyouni | — | Turns it into “~ly”, describing a verb. |
| Before a noun | 重要な〜 juuyouna〜 | — | How it attaches when it modifies a noun. |
| Conditional (~ば/なら) | 重要なら juuyounara | — | “if it is ~”. |
| Conditional (~たら) | 重要だったら juuyoudattara | — | “if / when it is ~”. The everyday conditional. |
| Become (~なる) | 重要になる juuyouninaru | 重要になります juuyouninarimasu | “becomes ~” — the change-of-state form. |
| Too much (~すぎる) | 重要すぎる juuyousugiru | 重要すぎます juuyousugimasu | “too ~”. |
| Looks ~ (~そう) | 重要そう juuyousou | 重要そうです juuyousoudesu | “looks / seems ~” from appearance. |
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Why it conjugates this way
Na-adjectives behave like nouns. The word itself never changes — you conjugate だ/です after it, and you need な to put it in front of a noun.
See the full rules in the adjective conjugation guide.