意外 (igai) conjugation
unexpected, surprising
意外 (いがい, igai) 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 | 意外だ igaida | 意外です igaidesu | The form you look up. Also the casual “is ~”. |
| Negative | 意外じゃない igaijanai | 意外じゃないです igaijanaidesu | “is not ~”. |
| Past | 意外だった igaidatta | 意外でした igaideshita | “was ~”. |
| Past negative | 意外じゃなかった igaijanakatta | 意外じゃなかったです igaijanakattadesu | “was not ~”. |
| Te-form | 意外で igaide | — | Links to the next clause: “~ and …”. |
| Adverb | 意外に igaini | — | Turns it into “~ly”, describing a verb. |
| Before a noun | 意外な〜 igaina〜 | — | How it attaches when it modifies a noun. |
| Conditional (~ば/なら) | 意外なら igainara | — | “if it is ~”. |
| Conditional (~たら) | 意外だったら igaidattara | — | “if / when it is ~”. The everyday conditional. |
| Become (~なる) | 意外になる igaininaru | 意外になります igaininarimasu | “becomes ~” — the change-of-state form. |
| Too much (~すぎる) | 意外すぎる igaisugiru | 意外すぎます igaisugimasu | “too ~”. |
| Looks ~ (~そう) | 意外そう igaisou | 意外そうです igaisoudesu | “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.