Eccentric snooker player might do this (9)

I believe the answer is:

screwball

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'eccentric' is the definition.
(I know that screwball is a type of eccentric)

I don't understand how the rest of the clue works.

(Other definitions for screwball that I've seen before include "Crazy (person)" , "odd fellow?" , "Wacky" , "Idiot" , "Zany" .)

I've seen this clue in The Times.

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