Cheddar, possibly — cheese, finally eaten by king (6)
I believe the answer is:
george
'king' is the definition.
(eg King George VI)
'cheddar possibly cheese finally eaten' is the wordplay.
'cheddar possibly' becomes 'gorge' (Cheddar Gorge is a gorge in Somerset).
'finally' says to take the final letters.
'eaten' is an insertion indicator.
The last letter of 'cheese' is 'e'.
'gorge' placed around 'e' is 'GEORGE'.
'by' acts as a link.
(Other definitions for george that I've seen before include "one in 3 the 12 30 [DROP the DEAD DONKEY]" , "Boy --; -- Clooney" , "Dragon slayer" , "Man rowing on holiday" , "Dragon-slaying saint" .)