すごい (sugoi) conjugation
terrific, great
すごい (すごい, sugoi) 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.
Written 凄い in kanji, but usually written in kana alone.
Conjugation table
| Form | Plain (casual) | Polite (~です) | When you use it |
|---|---|---|---|
| Dictionary / plain | すごい sugoi | すごいです sugoidesu | The form you look up. Also the casual “is ~”. |
| Negative | すごくない sugokunai | すごくないです sugokunaidesu | “is not ~”. |
| Past | すごかった sugokatta | すごかったです sugokattadesu | “was ~”. |
| Past negative | すごくなかった sugokunakatta | すごくなかったです sugokunakattadesu | “was not ~”. |
| Te-form | すごくて sugokute | — | Links to the next clause: “~ and …”. |
| Adverb | すごく sugoku | — | Turns it into “~ly”, describing a verb. |
| Before a noun | すごい〜 sugoi〜 | — | How it attaches when it modifies a noun. |
| Conditional (~ば/なら) | すごければ sugokereba | — | “if it is ~”. |
| Conditional (~たら) | すごかったら sugokattara | — | “if / when it is ~”. The everyday conditional. |
| Become (~なる) | すごくなる sugokunaru | すごくなります sugokunarimasu | “becomes ~” — the change-of-state form. |
| Too much (~すぎる) | すごすぎる sugosugiru | すごすぎます sugosugimasu | “too ~”. |
| Looks ~ (~そう) | すごそう sugosou | すごそうです sugosoudesu | “looks / seems ~” from appearance. |
🔊 Tap any Japanese word to hear it spoken.
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.