Korean 어이없다 (eoh-ee-up-dah)When you are rendered speechless by something someone has said or done because it was so assholeish/ridiculous/etc.

It was originally spelled 어의없다. But thanks to the ~~dumbing down~~ evolution of language and spelling, it is now spelled 어이없다. But Korean speakers may not notice the difference between the two. "어이" is derived from the old word "어처구니" (uh-chuh-goo-nee), which means "a person or object that is incredibly huge". The second part, "없다" means that it's not there. Therefore 어이없다 literally means "an incredibly huge person/object is not there" and is interpreted as that the person said/did something that was so huge, that you are rendered speechless. The funny thing about 어이없다 is that you can use it to describe you or the person you are 'insulting'. "Wow he is so 어이없어 - how can he say such a thing?" "I was so 어이없어 because of what he said, I stopped talking to him." "The whole situation is so 어이없어." Etc. (-없어 is a conjugation of -없다.)