主要 (shuyou) conjugation
chief, main
主要 (しゅよう, shuyou) 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 | 主要だ shuyouda | 主要です shuyoudesu | The form you look up. Also the casual “is ~”. |
| Negative | 主要じゃない shuyoujanai | 主要じゃないです shuyoujanaidesu | “is not ~”. |
| Past | 主要だった shuyoudatta | 主要でした shuyoudeshita | “was ~”. |
| Past negative | 主要じゃなかった shuyoujanakatta | 主要じゃなかったです shuyoujanakattadesu | “was not ~”. |
| Te-form | 主要で shuyoude | — | Links to the next clause: “~ and …”. |
| Adverb | 主要に shuyouni | — | Turns it into “~ly”, describing a verb. |
| Before a noun | 主要な〜 shuyouna〜 | — | How it attaches when it modifies a noun. |
| Conditional (~ば/なら) | 主要なら shuyounara | — | “if it is ~”. |
| Conditional (~たら) | 主要だったら shuyoudattara | — | “if / when it is ~”. The everyday conditional. |
| Become (~なる) | 主要になる shuyouninaru | 主要になります shuyouninarimasu | “becomes ~” — the change-of-state form. |
| Too much (~すぎる) | 主要すぎる shuyousugiru | 主要すぎます shuyousugimasu | “too ~”. |
| Looks ~ (~そう) | 主要そう shuyousou | 主要そうです shuyousoudesu | “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.