Kills aristocrats by beheading them (4)
I believe the answer is:
offs
'kills' is the definition.
(I've seen this in other clues)
'aristocrats by beheading them' is the wordplay.
I cannot really see how this works, but
'by' could be 'of' and 'of' is located in the answer.
This may be the basis of the clue (or it may be nonsense).
Can you help me to learn more?
(Other definitions for offs that I've seen before include "Californian kills" , "Leaves" , "ices" .)