Fit and size fancy furrier occasionally missed (7)

I believe the answer is:

seizure

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'fit' is the definition.
(I know that fit can be written as seizure)

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

Can you help me to learn more?

(Other definitions for seizure that I've seen before include "Taking possession by legal process" , "Sudden attack of illness" , "Sudden fit" , "Taking something" , "Apprehension" .)

I've seen this clue in The Telegraph.

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