The most common and most likely answer to this crossword clue is the 10 letter word KNOCKER-UP
I've seen this crossword clue in Independent
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Buddy explains!
The straight part
We know that "Rousing person" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case rousing person = knocker-up.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.
What does KNOCKER-UP mean?
KNOCKER-UP noun- A person whose job was to go from house to house in the early morning and wake up workers by tapping on the bedroom window with a long pole or similarly convenient implement.