The most common and most likely answer to this crossword clue is the 5 plus 4 letter word ROYAL BLUE
I've seen this crossword clue in Financial Times
R
O
Y
A
L
B
L
U
E
More clues leading to the result ROYAL BLUE
- After working, you're all black ... and another colour
- Ely with Labour turning a shade Conservative?
- Prince unhappy in the shade
- Boys spent unwisely, we hear? A shade
- Two blokes reportedly wasted cast
- The colour of blood?
- Colour of prince’s blood?
- Label your bananas in colour
- Queen dejected in the shade
- The colour of princely blood?
Buddy explains!
The straight part
We know that "cast" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case cast = royal blue.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.