racket (n.1) Look up racket at Dictionary.com
"loud noise," 1560s, said to be imitative. Meaning "dishonest activity" (1785) is perhaps from racquet, via notion of "game," reinforced by rack-rent "extortionate rent" (1590s), from rack (n.1).
racket (n.2) Look up racket at Dictionary.com
"bat used in tennis, etc.," see racquet.