結構 (kekkou) conjugation
splendid; enough, tolerably
結構 (けっこう, kekkou) 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 | 結構だ kekkouda | 結構です kekkoudesu | The form you look up. Also the casual “is ~”. |
| Negative | 結構じゃない kekkoujanai | 結構じゃないです kekkoujanaidesu | “is not ~”. |
| Past | 結構だった kekkoudatta | 結構でした kekkoudeshita | “was ~”. |
| Past negative | 結構じゃなかった kekkoujanakatta | 結構じゃなかったです kekkoujanakattadesu | “was not ~”. |
| Te-form | 結構で kekkoude | — | Links to the next clause: “~ and …”. |
| Adverb | 結構に kekkouni | — | Turns it into “~ly”, describing a verb. |
| Before a noun | 結構な〜 kekkouna〜 | — | How it attaches when it modifies a noun. |
| Conditional (~ば/なら) | 結構なら kekkounara | — | “if it is ~”. |
| Conditional (~たら) | 結構だったら kekkoudattara | — | “if / when it is ~”. The everyday conditional. |
| Become (~なる) | 結構になる kekkouninaru | 結構になります kekkouninarimasu | “becomes ~” — the change-of-state form. |
| Too much (~すぎる) | 結構すぎる kekkousugiru | 結構すぎます kekkousugimasu | “too ~”. |
| Looks ~ (~そう) | 結構そう kekkousou | 結構そうです kekkousoudesu | “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.