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on the contrary; rather; instead; all the more
薬を飲んだが、反って症状が悪くなった。
I took the medicine, but it made my symptoms worse instead.
急いだのに反って遅刻してしまった。
I hurried, yet ended up being late anyway.
反って彼の方が正しかったと思う。
On the contrary, I think he was the one who was right.