優秀 (yuushuu) conjugation
superiority, excellence
優秀 (ゆうしゅう, yuushuu) 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 | 優秀だ yuushuuda | 優秀です yuushuudesu | The form you look up. Also the casual “is ~”. |
| Negative | 優秀じゃない yuushuujanai | 優秀じゃないです yuushuujanaidesu | “is not ~”. |
| Past | 優秀だった yuushuudatta | 優秀でした yuushuudeshita | “was ~”. |
| Past negative | 優秀じゃなかった yuushuujanakatta | 優秀じゃなかったです yuushuujanakattadesu | “was not ~”. |
| Te-form | 優秀で yuushuude | — | Links to the next clause: “~ and …”. |
| Adverb | 優秀に yuushuuni | — | Turns it into “~ly”, describing a verb. |
| Before a noun | 優秀な〜 yuushuuna〜 | — | How it attaches when it modifies a noun. |
| Conditional (~ば/なら) | 優秀なら yuushuunara | — | “if it is ~”. |
| Conditional (~たら) | 優秀だったら yuushuudattara | — | “if / when it is ~”. The everyday conditional. |
| Become (~なる) | 優秀になる yuushuuninaru | 優秀になります yuushuuninarimasu | “becomes ~” — the change-of-state form. |
| Too much (~すぎる) | 優秀すぎる yuushuusugiru | 優秀すぎます yuushuusugimasu | “too ~”. |
| Looks ~ (~そう) | 優秀そう yuushuusou | 優秀そうです yuushuusoudesu | “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.