Parable misheard about Mark (7)
I believe the answer is:
blemish
'mark' is the definition.
(I know that blemish is a is a kind of of mark)
'parable misheard about' is the wordplay.
'about' says the answer is hidden in the clue (the clue goes around or about the answer).
'BLEMISH' is hidden within 'parable misheard'.
(Other definitions for blemish that I've seen before include "deformity" , "Moral defect or fault" , "Flaw; moral defect" , "Stain - defect" , "Noticeable flaw" .)