n.

a loud and disturbing noise

an illegal enterprise (such as extortion or fraud or drug peddling or prostitution) carried on for profit

同義詞：fraudulent schemeillegitimate enterprise

the auditory experience of sound that lacks musical quality; sound that is a disagreeable auditory experience

同義詞：noisedissonance

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

同義詞：racquet

Rackets
Kinks, Rings, and Rackets in Filamentous Structures
Reds or Rackets? The Making of Radical and Conservative Unions on the Waterfront
Nonaxisymmetric phospholipid vesicles: Rackets, boomerangs, and starfish
Emotion Measurements of Tennis Rackets on the basis of the Fractal Analysis of EEG
Probabilities and Decision Rules for the Game of Squash Rackets
The dynamic impact characteristics of tennis balls with tennis rackets
The tennis stroke: an EMG analysis of selected muscles with rackets of increasing grip size.
Central American maras: from youth street gangs to transnational protection rackets
Does illegality breed violence? Drug trafficking and state-sponsored protection rackets