The most common and most likely answer to this crossword clue is the 6 letter word ATONAL
I've seen this crossword clue in The Daily Telegraph
A
T
O
N
A
L
More clues leading to the result ATONAL
- Area with mostly lofty houses working without a key
- An alto struggling to describe music such as Schoenberg’s?
- Diplomat on a launch hiding without a key
- Like some music that could be rendered by an alto
- As drum-major he carries the bone
- A hundred and fifty without a . . . . without a key
- As modernist works in solo after a fashion, one discarded
- A huge amount, almost all discordant
- Lacking scales, a claw moves on
- Cheers up about a locksmith’s entrance without a key
Buddy explains!
The straight part
We know that "unlike much music" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case unlike much music = atonal.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 ATONAL mean?
ATONAL adjective- Lacking a tonal center or key.
- Not tonal, lacking tones.