五里霧中

プログレッシブ和英中辞典(第4版)

ごりむちゅう【五里霧中】

山中を五里霧中で歩き回った
They wandered through the mountains, totally lost.／They completely lost their bearings and wandered around on the mountain.

研究方法も分からず五里霧中だった
He was 「at a complete loss [completely in the dark] as to how to proceed with his research.

出典　小学館「プログレッシブ和英中辞典(第4版)」