How I get milk's not appropriate (5)

I believe the answer is:

inapt

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'not appropriate' is the definition.
(inapt means inappropriate or ill-fitting)

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

(Other definitions for inapt that I've seen before include "Not fit, unsuitable" , "unqualified" , "Improper" , "Not proper" , "Far from fit" .)

I've seen this clue in The Independent.

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