False note? What a pity! (5)
I believe the answer is:
shame
'what a pity' is the definition.
(synonyms)
'false note?' is the wordplay.
'false' becomes 'sham' (sham means fake or pretend).
'note?' becomes 'e' (musical note).
'sham'+'e'='SHAME'
(Other definitions for shame that I've seen before include "Painful emotion resulting from guilt" , "Disgrace - Salman Rushdie novel" , "Regrettable thing" , "Humiliation; dishonour" , "Disgrace, intense regret" .)