Racket is one disturbance (5)
I believe the answer is:
noise
I believe this clue is a double definition.
'racket is one' is the first definition.
(I know that racket is a type of noise)
'disturbance' is the second definition.
(I know that disturbance can be written as noise)
(Other definitions for noise that I've seen before include "Static - sound" , "Row" , "Hum" , "explosive report, for example" , "Kind of pollution" .)