To clobber is to beat up or to defeat soundly in a game. You can say your favorite baseball team clobbers the competition if they win with a score of 10 to 0.
When a boxer knocks out his adversary he clobbers him, and a bully clobbers his victim by punching him repeatedly. You can also clobber someone without shedding blood, as when you beat your dad in chess. The word clobber was originally World War II British air force slang, in the 1940s, and usually referred to aerial bombing.