Ali, Muhammad, ah LEE, moo HAHM uhd (1942-...), was an American heavyweight boxing champion. Ali first won the championship by knocking out Sonny Liston in 1964. Some boxing groups recognized Ali as champion until 1967. But he was stripped of the World Boxing Association (WBA) title late in 1964 in a dispute over a contract. The WBA again recognized Ali as champion after he defeated Ernie Terrell in 1967. In the same year, the WBA and other boxing groups stripped Ali of his title when he refused induction into the United States Army. He was also convicted on charges of refusing induction.