to listen attentively to; to be absorbed in (listening to)
彼の話に聞き入った。
I was absorbed in what he was saying.
子供たちは昔話に静かに聞き入っていた。
The children were quietly absorbed in the folktale.
演奏が始まると思わず聞き入ってしまう。
Once the performance begins I can't help getting drawn in.