He's empty headed, black hearted and loud! (3)
I believe the answer is:
oaf
'he's empty headed' is the definition.
The answer is a person as well as being a singular noun. This is suggested by the definition.
'black hearted and loud' is the wordplay.
'black' becomes 'coal black' (coal black is a kind of black).
'hearted' indicates the central letters.
'and' says to put letters next to each other.
'loud' becomes 'f' (short for forte - 'loud' in music).
The central letters of 'coal' are 'oa'.
'oa'+'f'='OAF'
Can you help me to learn more?
(Other definitions for oaf that I've seen before include "Stupid lout" , "Idiot" , "A clumsy or stupid person" , "Goon" , "Barbarian" .)