Exclamation of surprise or sudden realization, like when you just remembered something.
はっ、財布を忘れた！
Oh! I forgot my wallet!
Polite affirmative response, similar to はい but often sharper or more formal. Used in service or military contexts.
「了解しましたか？」「はっ！」
"Understood?" "Yes!"
Used when you didn't catch what someone said or are surprised by a statement. Can sound blunt.
はっ？ 今なんて言った？
Huh? What did you just say?
えっ expresses surprise or asking someone to repeat themselves in a softer way, whereas はっ can sound more blunt or confrontational in the same context.
フッ and ハッ both mimic a short exhalation, but ハッ usually expresses sudden surprise or realization, while フッ suggests a soft sigh or exertion.
Standard hiragana spelling for this interjection.
Katakana spelling, often used for emphasis or in casual writing.
The exact origin is uncertain; it is likely a natural exclamation that developed in spoken Japanese.