Aunt Sally, say, is permissible target (4,4)

I believe the answer is:

fair game

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'permissible target' is the definition.
(I've seen this before)

I don't understand the rest of the clue.

(Other definitions for fair game that I've seen before include "Aunt Sally, for instance" , "Legitimate target for attack or exploitation" , "Acceptable target?" , "permissible target" , "legitimate target for ridicule?" .)

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