素早い (subayai) conjugation
fast, quick
素早い (すばやい, subayai) is an i-adjective. I-adjectives carry their own tense: drop the final い and the endings attach straight to the stem. No だ, no です needed to make a complete sentence.
Conjugation table
| Form | Plain (casual) | Polite (~です) | When you use it |
|---|---|---|---|
| Dictionary / plain | 素早い subayai | 素早いです subayaidesu | The form you look up. Also the casual “is ~”. |
| Negative | 素早くない subayakunai | 素早くないです subayakunaidesu | “is not ~”. |
| Past | 素早かった subayakatta | 素早かったです subayakattadesu | “was ~”. |
| Past negative | 素早くなかった subayakunakatta | 素早くなかったです subayakunakattadesu | “was not ~”. |
| Te-form | 素早くて subayakute | — | Links to the next clause: “~ and …”. |
| Adverb | 素早く subayaku | — | Turns it into “~ly”, describing a verb. |
| Before a noun | 素早い〜 subayai〜 | — | How it attaches when it modifies a noun. |
| Conditional (~ば/なら) | 素早ければ subayakereba | — | “if it is ~”. |
| Conditional (~たら) | 素早かったら subayakattara | — | “if / when it is ~”. The everyday conditional. |
| Become (~なる) | 素早くなる subayakunaru | 素早くなります subayakunarimasu | “becomes ~” — the change-of-state form. |
| Too much (~すぎる) | 素早すぎる subayasugiru | 素早すぎます subayasugimasu | “too ~”. |
| Looks ~ (~そう) | 素早そう subayasou | 素早そうです subayasoudesu | “looks / seems ~” from appearance. |
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Why it conjugates this way
I-adjectives carry their own tense: drop the final い and the endings attach straight to the stem. No だ, no です needed to make a complete sentence.
See the full rules in the adjective conjugation guide.