平気 (heiki) conjugation
coolness, calmness, unconcern
平気 (へいき, heiki) 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 | 平気だ heikida | 平気です heikidesu | The form you look up. Also the casual “is ~”. |
| Negative | 平気じゃない heikijanai | 平気じゃないです heikijanaidesu | “is not ~”. |
| Past | 平気だった heikidatta | 平気でした heikideshita | “was ~”. |
| Past negative | 平気じゃなかった heikijanakatta | 平気じゃなかったです heikijanakattadesu | “was not ~”. |
| Te-form | 平気で heikide | — | Links to the next clause: “~ and …”. |
| Adverb | 平気に heikini | — | Turns it into “~ly”, describing a verb. |
| Before a noun | 平気な〜 heikina〜 | — | How it attaches when it modifies a noun. |
| Conditional (~ば/なら) | 平気なら heikinara | — | “if it is ~”. |
| Conditional (~たら) | 平気だったら heikidattara | — | “if / when it is ~”. The everyday conditional. |
| Become (~なる) | 平気になる heikininaru | 平気になります heikininarimasu | “becomes ~” — the change-of-state form. |
| Too much (~すぎる) | 平気すぎる heikisugiru | 平気すぎます heikisugimasu | “too ~”. |
| Looks ~ (~そう) | 平気そう heikisou | 平気そうです heikisoudesu | “looks / seems ~” from appearance. |
🔊 Tap any Japanese word to hear it spoken.
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.