The most common and most likely answer to this crossword clue is the 2 plus 3 plus 3 plus 6 letter word WE ARE NOT AMUSED
I've seen this crossword clue in Financial Times
W
E
A
R
E
N
O
T
A
M
U
S
E
D
More clues leading to the result WE ARE NOT AMUSED
- Royal rebuke where plant involves a Greek character in high treason
- Mate saw our need to change for the Victoria Line
- Don, a shade upset, considered royal rebuke
- Austere woman troubled journalist that had royal attribution
- Queen’s expression showing a tremendous awe? Not exactly
- What we might say when a joke falls flat
Buddy explains!
The straight part
We know that "Royal rebuke" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case royal rebuke = we are not amused.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.