複雑 (fukuzatsu) conjugation
complexity, complication
複雑 (ふくざつ, fukuzatsu) 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 | 複雑だ fukuzatsuda | 複雑です fukuzatsudesu | The form you look up. Also the casual “is ~”. |
| Negative | 複雑じゃない fukuzatsujanai | 複雑じゃないです fukuzatsujanaidesu | “is not ~”. |
| Past | 複雑だった fukuzatsudatta | 複雑でした fukuzatsudeshita | “was ~”. |
| Past negative | 複雑じゃなかった fukuzatsujanakatta | 複雑じゃなかったです fukuzatsujanakattadesu | “was not ~”. |
| Te-form | 複雑で fukuzatsude | — | Links to the next clause: “~ and …”. |
| Adverb | 複雑に fukuzatsuni | — | Turns it into “~ly”, describing a verb. |
| Before a noun | 複雑な〜 fukuzatsuna〜 | — | How it attaches when it modifies a noun. |
| Conditional (~ば/なら) | 複雑なら fukuzatsunara | — | “if it is ~”. |
| Conditional (~たら) | 複雑だったら fukuzatsudattara | — | “if / when it is ~”. The everyday conditional. |
| Become (~なる) | 複雑になる fukuzatsuninaru | 複雑になります fukuzatsuninarimasu | “becomes ~” — the change-of-state form. |
| Too much (~すぎる) | 複雑すぎる fukuzatsusugiru | 複雑すぎます fukuzatsusugimasu | “too ~”. |
| Looks ~ (~そう) | 複雑そう fukuzatsusou | 複雑そうです fukuzatsusoudesu | “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.