The term 'Cubs Slugger' refers to Sammy Sosa, a former Major League Baseball right fielder who played for the Chicago Cubs from 1992 to 2004. He was known for his powerful hitting and was one of the most popular players in the league during his time with the Cubs. Sosa is also remembered for his involvement in the 1998 home run race with Mark McGwire, which helped to revive interest in baseball. His last name, Sosa, is the four-letter solution to the crossword puzzle.