To use a certain way of doing something, especially when it's not the best choice and you have no other options.
When the power went out, they had to resort to using candles for light.
停電になったとき、彼らは明かりのためにろうそくを使わざるを得なかった。
To depend on a certain method or way, especially when it's extreme or not a good choice.
Out of options, they resorted to asking strangers for help.
選択肢がなくなったので、彼らは見知らぬ人に助けを求めざるを得なかった。