久しい (hisashii) conjugation
long, long-continued, old (story)
久しい (ひさしい, hisashii) 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 | 久しい hisashii | 久しいです hisashiidesu | The form you look up. Also the casual “is ~”. |
| Negative | 久しくない hisashikunai | 久しくないです hisashikunaidesu | “is not ~”. |
| Past | 久しかった hisashikatta | 久しかったです hisashikattadesu | “was ~”. |
| Past negative | 久しくなかった hisashikunakatta | 久しくなかったです hisashikunakattadesu | “was not ~”. |
| Te-form | 久しくて hisashikute | — | Links to the next clause: “~ and …”. |
| Adverb | 久しく hisashiku | — | Turns it into “~ly”, describing a verb. |
| Before a noun | 久しい〜 hisashii〜 | — | How it attaches when it modifies a noun. |
| Conditional (~ば/なら) | 久しければ hisashikereba | — | “if it is ~”. |
| Conditional (~たら) | 久しかったら hisashikattara | — | “if / when it is ~”. The everyday conditional. |
| Become (~なる) | 久しくなる hisashikunaru | 久しくなります hisashikunarimasu | “becomes ~” — the change-of-state form. |
| Too much (~すぎる) | 久しすぎる hisashisugiru | 久しすぎます hisashisugimasu | “too ~”. |
| Looks ~ (~そう) | 久しそう hisashisou | 久しそうです hisashisoudesu | “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.