너무하다 is similar to "(is) too much" in English, as 너무 is "too" or "too much", and 하다 is do or act. But it is normally used in the negative sense only, usually that a person or situation is too harsh, tough, difficult, etc. The underlying implication is someone or a situation being or acting beyond reasonable expectations. Here are examples from the Naver dictionary: (verb) - 해도 해도 너무한다 싶을 정도로 야박했다. => (They) were being cruel beyond all manners and expectations. - 해도 못 넘기고 신랑을 빼앗기다니 정말 너무하는 노릇이었다. => It was too much to have one's husband taken away even before one year. - 너무하건 말건 안 되는 것은 안 되는 것이네. => What can't be done can't be done whether it's too much or not. (adjective) -이렇게 무시하다니 너무하군. => What a treatment to despise us like this. -우리는 정말 세상일이 너무하다 싶었다. => It hit us hard how cruel the world seemed to us. -그는 묘목 한 그루에 만 원은 너무하지 않으냐고 사정사정했다. => He kept imploring with them that 10,000 won for a seedling tree was too much.