The most common and most likely answer to this crossword clue is the 10 letter word PIANISSIMO
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More clues leading to the result PIANISSIMO
- The beginning and end of pop that's scarcely audible?
- Very soft pine for one backing possibly grand houses
- Very soft bit of apple expanded
- Good old girl in a revolutionary, hardly heard?
- Very quiet shopping centre?
- Greek character on a strange mission — very hush-hush?
- Yapper keeps so very quiet!
- Episcopalianism sadly has no place for instruction of organists?
Buddy explains!

The straight part
We know that "instruction of organists?" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case instruction of organists? = pianissimo.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 PIANISSIMO mean?
PIANISSIMO noun- A dynamic sign indicating that a portion of music should be played pianissimo.
- A portion of music that is played very softly.
- To be played very softly.