冷酷 (reikoku) conjugation
cruelty, coldheartedness, ruthless
冷酷 (れいこく, reikoku) 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 | 冷酷だ reikokuda | 冷酷です reikokudesu | The form you look up. Also the casual “is ~”. |
| Negative | 冷酷じゃない reikokujanai | 冷酷じゃないです reikokujanaidesu | “is not ~”. |
| Past | 冷酷だった reikokudatta | 冷酷でした reikokudeshita | “was ~”. |
| Past negative | 冷酷じゃなかった reikokujanakatta | 冷酷じゃなかったです reikokujanakattadesu | “was not ~”. |
| Te-form | 冷酷で reikokude | — | Links to the next clause: “~ and …”. |
| Adverb | 冷酷に reikokuni | — | Turns it into “~ly”, describing a verb. |
| Before a noun | 冷酷な〜 reikokuna〜 | — | How it attaches when it modifies a noun. |
| Conditional (~ば/なら) | 冷酷なら reikokunara | — | “if it is ~”. |
| Conditional (~たら) | 冷酷だったら reikokudattara | — | “if / when it is ~”. The everyday conditional. |
| Become (~なる) | 冷酷になる reikokuninaru | 冷酷になります reikokuninarimasu | “becomes ~” — the change-of-state form. |
| Too much (~すぎる) | 冷酷すぎる reikokusugiru | 冷酷すぎます reikokusugimasu | “too ~”. |
| Looks ~ (~そう) | 冷酷そう reikokusou | 冷酷そうです reikokusoudesu | “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.