Well-disciplined medical attendant (7)

I believe the answer is:

orderly

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'attendant' is the definition.
(I know that orderly is a type of attendant)

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

Can you help me to learn more?

(Other definitions for orderly that I've seen before include "Regular - neat" , "Methodical; hospital worker" , "Hospital or military attendant" , "Businesslike" , "Tidy officer's attendant" .)

I've seen this clue in The Irish News.

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