Top soprano initially improvises (7)
I believe the answer is:
noodles
'initially improvises' is the definition.
I can't judge whether this defines the answer.
'top soprano' is the wordplay.
I cannot quite see how this works, but
'soprano' could be 's' (musical abbreviation) and 's' is found within the answer.
The remaining letters 'noodle' is a valid word which might be clued in a way I don't see.
This may be the basis of clue (or it may be nonsense).
Can you help me to learn more?
(Other definitions for noodles that I've seen before include "Simpletons (colloq.)" , "Oriental pasta" , "Far Eastern food" , "Fools; pasta" , "Pasta ribbons" .)