軽快 (keikai) conjugation
lively, casual, light
軽快 (けいかい, keikai) 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 | 軽快だ keikaida | 軽快です keikaidesu | The form you look up. Also the casual “is ~”. |
| Negative | 軽快じゃない keikaijanai | 軽快じゃないです keikaijanaidesu | “is not ~”. |
| Past | 軽快だった keikaidatta | 軽快でした keikaideshita | “was ~”. |
| Past negative | 軽快じゃなかった keikaijanakatta | 軽快じゃなかったです keikaijanakattadesu | “was not ~”. |
| Te-form | 軽快で keikaide | — | Links to the next clause: “~ and …”. |
| Adverb | 軽快に keikaini | — | Turns it into “~ly”, describing a verb. |
| Before a noun | 軽快な〜 keikaina〜 | — | How it attaches when it modifies a noun. |
| Conditional (~ば/なら) | 軽快なら keikainara | — | “if it is ~”. |
| Conditional (~たら) | 軽快だったら keikaidattara | — | “if / when it is ~”. The everyday conditional. |
| Become (~なる) | 軽快になる keikaininaru | 軽快になります keikaininarimasu | “becomes ~” — the change-of-state form. |
| Too much (~すぎる) | 軽快すぎる keikaisugiru | 軽快すぎます keikaisugimasu | “too ~”. |
| Looks ~ (~そう) | 軽快そう keikaisou | 軽快そうです keikaisoudesu | “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.