"knucklehead" in Chinese (Simplified)
笨蛋傻瓜
Definition
形容一个傻乎乎或愚笨的人，通常是友好或开玩笑的方式，而非真正侮辱。
Usage Notes (Chinese (Simplified))
很随意和玩笑，通常对熟悉的人说，类似于'傻瓜'。不是强烈的批评，不建议对陌生人说。
Examples
Don't be a knucklehead and forget your homework again.
别当个**笨蛋**，再忘了作业。
His sister called him a knucklehead after he dropped the cake.
他妹妹在他掉了蛋糕后叫他**笨蛋**。
It's just a joke, you knucklehead!
只是个玩笑，你这个**傻瓜**！
You locked your keys in the car again? What a knucklehead!
你又把钥匙锁车里了？真是个**笨蛋**！
Sometimes my brother acts like a total knucklehead, but I still love him.
有时候我哥哥真的很**傻瓜**，但我还是爱他。
Only a knucklehead would try to fix the TV with a hammer.
只有**笨蛋**才会用锤子修电视。