単純 (tanjun) conjugation
simplicity
単純 (たんじゅん, tanjun) 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 | 単純だ tanjunda | 単純です tanjundesu | The form you look up. Also the casual “is ~”. |
| Negative | 単純じゃない tanjunjanai | 単純じゃないです tanjunjanaidesu | “is not ~”. |
| Past | 単純だった tanjundatta | 単純でした tanjundeshita | “was ~”. |
| Past negative | 単純じゃなかった tanjunjanakatta | 単純じゃなかったです tanjunjanakattadesu | “was not ~”. |
| Te-form | 単純で tanjunde | — | Links to the next clause: “~ and …”. |
| Adverb | 単純に tanjunni | — | Turns it into “~ly”, describing a verb. |
| Before a noun | 単純な〜 tanjunna〜 | — | How it attaches when it modifies a noun. |
| Conditional (~ば/なら) | 単純なら tanjunnara | — | “if it is ~”. |
| Conditional (~たら) | 単純だったら tanjundattara | — | “if / when it is ~”. The everyday conditional. |
| Become (~なる) | 単純になる tanjunninaru | 単純になります tanjunninarimasu | “becomes ~” — the change-of-state form. |
| Too much (~すぎる) | 単純すぎる tanjunsugiru | 単純すぎます tanjunsugimasu | “too ~”. |
| Looks ~ (~そう) | 単純そう tanjunsou | 単純そうです tanjunsoudesu | “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.