Lament returning unfinished crossword? (4)

I believe the answer is:

grid

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'crossword?' is the definition.
(a crossword grid)

I don't understand the rest of the clue.

(Other definitions for grid that I've seen before include "What's above these clues" , "Barred framework" , "puzzle diagram" , "Pattern of crossing lines" , "Network of crossing parallel lines" .)

I've seen this clue in The Independent.

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