The most common and most likely answer to this crossword clue is the 10 letter word HANOVERIAN
H
A
N
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V
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I
A
N
More clues leading to the result HANOVERIAN
- From a noble family – a Chinese dynasty – superior to Scotsman
- Hour man needs to collect a series of deliveries in royal house
- After-effect of drink knocking out good Scot in a royal house
- Royal family’s survival after removal of head of government by Scotsman
- The effect of drinking with no good Scotsman of a royal house
Buddy explains!

The straight part
We know that "Royal family’s" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case royal family’s = hanoverian.The cryptic/wordplay part
In cryptic crossword there's often an wordplay/cryptic part as well.This part involves a more complex hint, such as an anagram, homophone, hidden word, etc.
Sadly, We don't have an explanation for this specific crossword clue yet.