The most common and most likely answer to this crossword clue is the 6 letter word LYRIST
I've seen this crossword clue in The Times
L
Y
R
I
S
T
More clues leading to the result LYRIST
Buddy explains!

The straight part
We know that "a musician" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case a musician = lyrist.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 LYRIST mean?
LYRIST noun- A person who plays the lyre.
- Lyricist
- A lyrical poet