Be markedly sharper than one’s opponent (8)
I believe the answer is:
outpoint
'markedly sharper than one's opponent' is the definition.
I can't judge whether this definition defines the answer.
'be' is the wordplay.
I cannot quite understand how this works, but
'be' could be 'point' (pointing is a kind of being) and 'point' is found within the answer.
The remaining letters 'out' is a valid word which might be clued in a way I don't see.
This may be the basis of clue (or it may be nonsense).
Can you help me to learn more?
(Another definition for outpoint that I've seen is " Score more".)