Note, part of lush arpeggio? (5)
I believe the answer is:
sharp
'note' is the definition.
(thesaurus)
'part of lush arpeggio?' is the wordplay.
'part of' says the answer is hidden in the clue.
'SHARP' can be found hidden inside 'lush arpeggio'.
(Other definitions for sharp that I've seen before include "Note astute" , "Incisive" , "Mentally acute" , "tart" , "woman's name in Vanity Fair" .)