Show a note to some chap (6)
I believe the answer is:
evince
'show' is the definition.
(I know that show can be written as evince)
'a note to some chap' is the wordplay.
'a note' becomes 'e' (musical note).
'to some chap' becomes 'vince' ().
'e'+'vince'='EVINCE'
(Other definitions for evince that I've seen before include "Indicate or display, say a feeling" , "Make evident" , "Show or display, say feeling" , "Indicate, show clearly" , "Express,show" .)