Batsman shows character before showing knife (6,6)
I believe the answer is:
letter opener
'knife' is the definition.
(letter opener is a kind of knife)
'batsman shows character before' is the wordplay.
I cannot quite see how this works, but
'batsman' could be 'opener' (I've seen this before) and 'opener' is present in the answer.
'character' could be 'letter' (synonyms) and 'letter' is present in the answer.
This accounts for all the letters.
This may be the basis of the clue (or it may be nonsense).
'showing' is the link.
Can you help me to learn more?
(Other definitions for letter opener that I've seen before include "Knife for slitting envelopes" , "Dear (usually)" , "device for getting information from correspondents out" , "Implement for tearing envelopes" , "which could be dear, eg" .)