Cliff Clavin is a fictional character from the popular television show Cheers, which aired from 1982 to 1993. He is portrayed by actor John Ratzenberger and is known for his quirky personality and vast, often questionable knowledge. As a mailman, Cliff frequently shares random trivia and facts, much to the amusement and annoyance of his friends at the bar. Cliff is characterized by his distinctive look, often wearing a postal uniform and a baseball cap. His interactions with other characters, especially Norm Peterson, provide comedic relief and highlight his endearing yet clueless nature. Despite his eccentricities, Cliff is a loyal friend and a beloved member of the Cheers ensemble.