軽はずみ

君が彼の申し出を受けるとは軽はずみだったね。

It was foolish of you to accept his offer.

実地は理論と同様に大切であるが、われわれは理論を重んじ、実地を軽んずる傾向がある。

Practice is as important as theory, but we are apt to value the latter and despise the former.

えりのスーツケースは重たそうだが、実際はとても軽い。

Although Eri's suitcase looks heavy, it's actually very light.