Target ring where victor lost his head (5)
I believe the answer is:
inner
'target' is the definition.
(I've seen this before)
I don't understand the remainder of the clue.
Can you help me to learn more?
(Other definitions for inner that I've seen before include "Ring round bulls-eye" , "(Hit on) part of target immediately next to the bullseye" , "Annulus nearest bull" , "Concealed" , "Situated inside" .)