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hmm; well ...; humph; huh; pshaw; pish
roughly; harshly; violently
ふん、そんなこと知らしらない。
Hmph, I don't know about that.
ふん、どうでもいいよ。
Hmm, I don't care.
ふん、勝手かってにすれば。
Humph, do what you want.