Headless spirit is miserable (4)
I believe the answer is:
punk
'miserable' is the definition.
Both the definition and answer are adjectives. Perhaps you can see an association between them that I don't see?
'headless spirit' is the wordplay.
'headless' means to remove the first letter.
'spirit' becomes 'spunk' (spunk is a kind of spirit).
'spunk' with its initial letter removed is 'PUNK'.
'is' acts as a link.
Can you help me to learn more?
(Other definitions for punk that I've seen before include "Aggressive style of rock" , "Worthless person; seventies rock style" , "Type of rock music" , "Sex Pistols' movement" , "Rebellious 1970s youth" .)