Sound made by a person who's lost his head? (5)
I believe the answer is:
snore
'sound' is the definition.
(snore is a kind of sound)
I don't understand the rest of the clue.
Can you help me to learn more?
(Other definitions for snore that I've seen before include "6 made by sleeper" , "Make raucous nasal sound during sleep" , "How to keep someone awake while sleeping?" , "thing which bores" , "Make racous nocturnal sound" .)