Dissident

A dissident is someone who speaks up and expresses opinions that go against what most other people believe. Dissidents challenge existing rules and beliefs, and they are often seen as a courageous voice for change. For example, during the Civil Rights Movement, Martin Luther King Jr., was a dissident who spoke out against segregated public institutions, which at the time had been the accepted way of life. He caused people to think differently and ultimately helped bring about important changes in the United States.