Funny fabulist pulling good man's leg to a certain extent (6)
I believe the answer is:
fibula
'extent' is the definition.
Although both the answer and definition are singular nouns, I cannot see how they can define each other.
I cannot understand how the rest of the clue works.
Can you help me to learn more?
(Other definitions for fibula that I've seen before include "A lower-leg bone" , "Bone of the lower leg" , "Human leg-bone" , "Outer bone in the calf" .)
