racket (n.1)

"loud, disorderly, confusing noise," 1560s, probably imitative. Klein and Century Dictionary compare Gaelic racaid "noise, disturbance," but OED says this "is no doubt from Eng."

Meaning "dishonest activity" (1785) is perhaps an extended sense, from the notion of "something going on" or "noise or disturbance made to distract a pick-pocket's victim." Or it might be from racquet, via the notion of "a game," or from or reinforced by rack-rent "extortionate rent." There also was a verb racket "carry on eager or energetic action" (1753), and the gangster sense might be via the notion of "exciting and unusual." Weakened sense of "way of life, one's line of business" is by 1891.

racket (n.2)

"handled paddle or netted bat used in tennis, etc.;" see racquet.

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Definitions of racket from WordNet
racket (n.)
a loud and disturbing noise;
racket (n.)
an illegal enterprise (such as extortion or fraud or drug peddling or prostitution) carried on for profit;
Synonyms: fraudulent scheme / illegitimate enterprise
racket (n.)
the auditory experience of sound that lacks musical quality; sound that is a disagreeable auditory experience;
Synonyms: noise / dissonance
racket (n.)
a sports implement (usually consisting of a handle and an oval frame with a tightly interlaced network of strings) used to strike a ball (or shuttlecock) in various games;
Synonyms: racquet
racket (v.)
celebrate noisily, often indulging in drinking; engage in uproarious festivities;
Synonyms: revel / make whoopie / make merry / make happy / whoop it up / jollify / wassail
racket (v.)
make loud and annoying noises;
racket (v.)
hit (a ball) with a racket;