Right or wrong mark? Put off comprehending that (6)
I believe the answer is:
dexter
'right' is the definition.
(heraldic term for right)
'wrong mark? put off comprehending that' is the wordplay.
I cannot really see how this works, but
'wrong' could be 'x' (X is used to mark something as incorrect) and 'x' is present in the answer.
'put off' could be 'deter' (both can mean to discourage) and 'deter' is present in the leftover letters.
No letters remain.
This explanation may well be incorrect...
'or' is the link.
Can you help me to learn more?
(Other definitions for dexter that I've seen before include "Crime author" , "In heraldry, of or on the right side" , "breed of cattle from Ireland" , "Crime writer" , "Breed of cattle; right" .)