濃い (koi) conjugation
thick (as of color, liquid), dense, strong
濃い (こい, koi) 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 | 濃い koi | 濃いです koidesu | The form you look up. Also the casual “is ~”. |
| Negative | 濃くない kokunai | 濃くないです kokunaidesu | “is not ~”. |
| Past | 濃かった kokatta | 濃かったです kokattadesu | “was ~”. |
| Past negative | 濃くなかった kokunakatta | 濃くなかったです kokunakattadesu | “was not ~”. |
| Te-form | 濃くて kokute | — | Links to the next clause: “~ and …”. |
| Adverb | 濃く koku | — | Turns it into “~ly”, describing a verb. |
| Before a noun | 濃い〜 koi〜 | — | How it attaches when it modifies a noun. |
| Conditional (~ば/なら) | 濃ければ kokereba | — | “if it is ~”. |
| Conditional (~たら) | 濃かったら kokattara | — | “if / when it is ~”. The everyday conditional. |
| Become (~なる) | 濃くなる kokunaru | 濃くなります kokunarimasu | “becomes ~” — the change-of-state form. |
| Too much (~すぎる) | 濃すぎる kosugiru | 濃すぎます kosugimasu | “too ~”. |
| Looks ~ (~そう) | 濃そう kosou | 濃そうです kosoudesu | “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.