Definition
to render oneself unconscious, typically by striking the head
昏倒（常因碰撞頭部）
Be careful of that threshold, or you might knock yourself out by accidentally hitting your head.
小心那個門檻，否則你可能會不小心撞到頭，讓自己失去知覺。
While playing with his friends, he accidentally fell to the ground and knocked himself out.
和朋友玩耍時，他不小心摔倒在地上，讓自己失去了知覺。
If you're not careful and hit your head, you could knock yourself out.
如果你不小心撞到頭，可能會讓自己失去知覺。
to exhaust oneself to the point of illness
累壞
He pushed himself to run thirty kilometers in the marathon, and in the end, he really knocked himself out.
他讓自己在馬拉松中跑了三十公里，最後真的把自己累垮了。
If you work all day without a break, you'll soon knock yourself out.
如果你整天工作不休息，很快就會把自己累垮。
She studied hard for the exam and ended up knocking herself out.
她為考試努力學習，結果把自己累垮了。