Morning attire? (5)

I believe the answer is:

getup

I'm a little stuck... Click here to teach me more about this clue!

This clue could be a double definition.

'morning' is the first definition.
Although both the answer and definition are singular nouns, I can't understand how one could define the other.

'attire?' is the second definition.
(I know that getup is a type of attire)

Can you help me to learn more?

(Other definitions for getup that I've seen before include "clothes > stand" , "Study" .)

I've seen this clue in the Evening Standard.

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