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to indulge in; to give oneself up to; to be obsessed by
to be engrossed in; to be lost in; to be absorbed in
酒にふけるのは健康に良くないと医者に注意された。
The doctor warned me that indulging in alcohol is not good for my health.
彼は研究にふけるあまり食事も忘れてしまう。
He gets so absorbed in research that he even forgets to eat.
哀愁にふけって一人で夜を過ごした。
She spent the night alone, sunk in melancholy.