If you say that someone overreacts to something, you mean that they have and show more of an emotion than is necessary or appropriate.
例句
Is the council right to be concerned, or is it overreacting?...市政委员会表示关切是合情合理呢，还是反应过激？The market appeared to overreact, but this is not the case...市场反应看似过激，但实际并非如此。
英汉词典释义
vi.
反应过火
Some people overreacted to what was only a throwaway remark.有些人对随便说出的一句话反应过敏了。