本腰を入れる

ほんごしをいれる

to set about in earnest; to make a strenuous effort; to put one's back into (doing)

expression verb

Example sentences

俺（おれ）は慌（あわ）てて探し物（さがしもの）に本腰（ほんごし）を入（い）れ始（はじ）めた。

I hurriedly started searching in earnest.