Said of one who is regarded unfavorably, often because their reputation has been tarnished. Despite predating Abraham Lincoln's assassination, the phrase is often said to refer to Dr. Samuel Mudd, who was jailed for treating John Wilkes Booth after Booth shot Lincoln. Now that staff knows that I'm the one who proposed the layoffs, my name is mud. His name is mud now that he's been found guilty of embezzling money from the company.