The most common and most likely answer to this crossword clue is the 9 letter word CANTABILE
I've seen this crossword clue in The Times
C
A
N
T
A
B
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L
E
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The straight part
We know that "Melodious rendition" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case melodious rendition = cantabile.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 CANTABILE mean?
CANTABILE noun- A tempo mark directing that a passage is to be played in a lyrical manner
- A passage having this mark
- Describing a passage having this mark; singable, lyrical
- Played in this style; singingly, lyrically