A four-character idiom meaning total exhaustion — being utterly worn out physically and mentally. Frequently used in written or emphatic speech.
徹夜続きで疲労困憊のため、今日は休むことにした。
After consecutive all-nighters and total exhaustion, I decided to rest today.
マラソンの後で彼は疲労困憊してベンチに座り込んだ。
After the marathon he was completely exhausted and collapsed onto a bench.
忙しいプロジェクトのせいでチーム全体が疲労困憊している。
The busy project has left the whole team utterly exhausted.