Person who tries to get started, possibly, but not quite finished (6)

I believe the answer is:

taster

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'person' is the definition.
(taster is a kind of person)

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

(Other definitions for taster that I've seen before include "person in charge of testing" , "A sample to try" , "extract" , "Food tester" , "Sample intended to stimulate interest" .)

I've seen this clue in the Evening Standard.

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