A "muckraker" refers to journalists and writers in the early 20th century who investigated and exposed corruption, social injustices, and abuses of power. The term originated from Theodore Roosevelt, who used it to describe those who focused on the negative aspects of society, often uncovering scandals in politics and business. Muckrakers played a crucial role in the Progressive Era, bringing attention to issues like child labor, unsafe working conditions, and political corruption. Their work led to significant reforms, including improved labor laws and regulations, as they aimed to inform the public and promote social change through their investigative reporting.