A lost garment? (5)

I believe the answer is:

shirt

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'garment?' is the definition.
(I know that shirt is a type of garment)

I don't understand the remainder of the clue.

(Other definitions for shirt that I've seen before include "Man's garment" , "One may lose it at the bookie's" , "Male garment worn with tie" , "tailored garment" , "Garment for upper male body, usually cotton" .)

I've seen this clue in the Evening Standard.

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