One making the cut? (5)

I think it could be either:

Which length description are you looking for?:

knife

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'the cut?' is the definition.
(I've seen this before)

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

(Other definitions for knife that I've seen before include "Cutlery item" , "following Stanley perhaps" , "Cutting instrument" , "Carver" , "Cutting tool" .)

I've seen this clue in The Sun.

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