迅速 (jinsoku) conjugation
quick, fast, prompt
迅速 (じんそく, jinsoku) 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 | 迅速だ jinsokuda | 迅速です jinsokudesu | The form you look up. Also the casual “is ~”. |
| Negative | 迅速じゃない jinsokujanai | 迅速じゃないです jinsokujanaidesu | “is not ~”. |
| Past | 迅速だった jinsokudatta | 迅速でした jinsokudeshita | “was ~”. |
| Past negative | 迅速じゃなかった jinsokujanakatta | 迅速じゃなかったです jinsokujanakattadesu | “was not ~”. |
| Te-form | 迅速で jinsokude | — | Links to the next clause: “~ and …”. |
| Adverb | 迅速に jinsokuni | — | Turns it into “~ly”, describing a verb. |
| Before a noun | 迅速な〜 jinsokuna〜 | — | How it attaches when it modifies a noun. |
| Conditional (~ば/なら) | 迅速なら jinsokunara | — | “if it is ~”. |
| Conditional (~たら) | 迅速だったら jinsokudattara | — | “if / when it is ~”. The everyday conditional. |
| Become (~なる) | 迅速になる jinsokuninaru | 迅速になります jinsokuninarimasu | “becomes ~” — the change-of-state form. |
| Too much (~すぎる) | 迅速すぎる jinsokusugiru | 迅速すぎます jinsokusugimasu | “too ~”. |
| Looks ~ (~そう) | 迅速そう jinsokusou | 迅速そうです jinsokusoudesu | “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.