Note concerning grisly man (7)
I believe the answer is:
gregory
'man' is the definition.
'note concerning grisly' is the wordplay.
'note' becomes 'g' (musical note).
'concerning' becomes 're' (both can mean on a particular topic).
'grisly' becomes 'gory' (I've seen this before).
'g'+'re'+'gory'='GREGORY'
(Other definitions for gregory that I've seen before include "Boy's name meaning "watcher"" , "Calendar-reforming pope" , "boy" , "pope, perhaps" .)