The most common and most likely answer to this crossword clue is the 8 letter word MARQUISE
M
A
R
Q
U
I
S
E
Buddy explains!

The straight part
We know that "Noblewoman" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case noblewoman = marquise.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 MARQUISE mean?
MARQUISE noun- A marchioness, especially one who is French.
- A marquee.
- (jewelry) An oval cut diamond with pointed ends.
- A canopy, usually of glass, set as a shelter over a door opening onto a terrace or pavement.
- A style of parasol of the mid-19th century.
- A rich dessert made with dark chocolate, butter, sugar, cocoa powder, eggs and cream.