McCarthyism refers to a period in the early 1950s in the United States when Senator Joseph McCarthy led a campaign against alleged communists in the government and other sectors. This era was marked by intense fear of communism, fueled by the Cold War. Many people were accused without proper evidence, leading to ruined careers and lives. The term "McCarthyism" has since come to symbolize the practice of making accusations without sufficient evidence, often driven by fear and paranoia. It serves as a reminder of the dangers of political repression and the importance of protecting civil liberties in a democratic society.