Music beloved of the French, with variable piercing note (7)
I believe the answer is:
scherzo
'music' is the definition.
(scherzo is a kind of music)
'beloved of the french with variable piercing note' is the wordplay.
'beloved of the french' becomes 'cher' (term of endearment in French).
'with' is a charade indicator (letters next to each other).
'variable' becomes 'z' (algebra).
'piercing' means one lot of letters goes inside another (some letters pierce a hole in others).
'note' becomes 'so' (musical note).
'cher'+'z'='cherz'
'cherz' going within 'so' is 'SCHERZO'.
(Other definitions for scherzo that I've seen before include "Light, playful composition" , "Light or playful movement" , "One often with trio" , "Eg acquiring this lively piece" , "Fast musical movement" .)