왜(요)?
Why?

왜 나한테 이러는 거예요? : Why are you doing this to me?

왜 여기 있어요? : Why are you here?

왜 안 했어요? : Why didn’t you do it?

왜 그렇게 생각해요? : Why do you think that?

왜 도망가요? : Why are you running (away)

anime, gif, and handsome image

Even though 왜(요) has only one translation; why, sometimes in certain contexts it can be used to mean what.

is only translated to mean what when:

Asking asking the reason why someone is doing something
Example:

Person A: stares at person B

Person B: 왜?

Explanation: In English if you say caught someone staring at you then you say What (are you looking at)? but in Korean 왜(요)? can be used and it holds the meaning of why (are you looking at me).