The most common and most likely answer to this crossword clue is the 8 letter word VIRTUOSO
I've seen this crossword clue in Financial Times
V
I
R
T
U
O
S
O
More clues leading to the result VIRTUOSO
- Upright, not upper class, old expert musician
- Good university's missing old master
- Returning inside, shoos out rival master
- Very good turn-out, old musician
- Ivor’s out to become a skilled performer
- Leading expert got rogue virus, too
- Six tours organised with opera’s principal star performer
- Whizz kids regularly tour around with very ordinary clothing
- Maestro opposes riotous composition
- Expert first violin is leader of orchestra — about to turn out right?
Buddy explains!

The straight part
We know that "master" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case master = virtuoso.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 VIRTUOSO mean?
VIRTUOSO noun- An expert in virtù or art objects and antiquities; a connoisseur.
- Someone with special skill or knowledge; an expert.
- Specifically, a musician (or other performer) with masterly ability, technique, or personal style.
- Exhibiting the ability of a virtuoso.