Hearsay about head part (3)
I believe the answer is:
ear
'head part' is the definition.
('ear' is part of 'head')
'hearsay about' is the wordplay.
'about' indicates the answer is hidden within the clue.
'EAR' is hidden in the letters of 'hearsay'.
(Other definitions for ear that I've seen before include "cut" , "Seed container" , "Place for a plug" , "Ability to recognise sounds" , "Attention; an organ" .)