The most common and most likely answer to this crossword clue is the 7 letter word DRACULA
I've seen this crossword clue in The Guardian
D
R
A
C
U
L
A
More clues leading to the result DRACULA
- Count up a large university club for one
- Doctor and a copper taking on the French vampire
- Blood Count?
- Way retired copper enters in manner of vampire
- Perhaps King is rejected; likewise, the odd bits of Pullman novel
- Student union card revoked by a monster
- Capone with posh character upset one with an interest in 14?
- Count 10, possibly, backwards, before Cockney dance?
- A liberal, upper-class character recalled in horror novel
- Horrifying figure, character rising up, calculating to the core
Buddy explains!
The straight part
We know that "wicked nobleman" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case wicked nobleman = dracula.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.