不潔 (fuketsu) conjugation
unclean, dirty
不潔 (ふけつ, fuketsu) 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 | 不潔だ fuketsuda | 不潔です fuketsudesu | The form you look up. Also the casual “is ~”. |
| Negative | 不潔じゃない fuketsujanai | 不潔じゃないです fuketsujanaidesu | “is not ~”. |
| Past | 不潔だった fuketsudatta | 不潔でした fuketsudeshita | “was ~”. |
| Past negative | 不潔じゃなかった fuketsujanakatta | 不潔じゃなかったです fuketsujanakattadesu | “was not ~”. |
| Te-form | 不潔で fuketsude | — | Links to the next clause: “~ and …”. |
| Adverb | 不潔に fuketsuni | — | Turns it into “~ly”, describing a verb. |
| Before a noun | 不潔な〜 fuketsuna〜 | — | How it attaches when it modifies a noun. |
| Conditional (~ば/なら) | 不潔なら fuketsunara | — | “if it is ~”. |
| Conditional (~たら) | 不潔だったら fuketsudattara | — | “if / when it is ~”. The everyday conditional. |
| Become (~なる) | 不潔になる fuketsuninaru | 不潔になります fuketsuninarimasu | “becomes ~” — the change-of-state form. |
| Too much (~すぎる) | 不潔すぎる fuketsusugiru | 不潔すぎます fuketsusugimasu | “too ~”. |
| Looks ~ (~そう) | 不潔そう fuketsusou | 不潔そうです fuketsusoudesu | “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.