1To lean in or peer closely into something; to look into something by moving closer.
窓から部屋の中を覗き込むと、子どもたちが遊んでいた。
When I peered into the room through the window, the children were playing.
箱の中を覗き込んだら、古い手紙が出てきた。
I peered into the box and found some old letters.
彼は説明書を覗き込んで、組み立て方を確かめた。
He leaned over the manual to check how to assemble it.