King Lear, his head in conclusion off? (7,1)
I believe the answer is:
'king' is the definition.
(Charles I, King of England 1625-1649)
'lear his head in conclusion off?' is the wordplay.
'head in' indicates taking the first letters.
'off?' indicates anagramming the letters (I've seen 'off' mean this).
The first letter of 'conclusion' is 'c'.
'learhisc' anagrammed gives 'CHARLES I'.