Said to overlook royal stuff ups by proofreaders (9)

I believe the answer is:

misprints

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'ups by proofreaders' is the definition.
I can't tell whether this defines the answer.

'said to overlook royal stuff' is the wordplay.
'said' shows a homophone (sound like).
'to overlook' becomes 'miss' (synonyms).
'royal stuff' becomes 'prints' (I can't justify this - if you can you should believe this answer much more).
'miss' sounds like 'mis'.
'mis'+'prints'='MISPRINTS'

Can you help me to learn more?

(Another definition for misprints that I've seen is " Slips".)

I've seen this clue in the Sydney Morning Herald.

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