frazzle

1. PHRASE If you wear yourself to a frazzle, or if you are worn to a frazzle, you feel mentally and physically exhausted because you have been working too hard or because you have been constantly worrying about something. 精疲力竭的

She's worn to a frazzle with her silly speech competition. 她被自己愚蠢的演讲比赛搞得精疲力竭。