Easy chance for poser (6)

I believe the answer is:

sitter

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'poser' is the definition.
(I have seen 'A poser' mean 'sitter' so perhaps 'poser' could also mean 'sitter')

I cannot understand how the remainder of the clue works.

Can you help me to learn more?

(Other definitions for sitter that I've seen before include "Model - childminder" , "One minds the baby" , "Easy shot or catch" , "broody type" , "Sedentary baby minder?" .)

I've seen this clue in The Sun.

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