Pinch a sound knife sharpener (5)
I believe the answer is:
steal
'pinch' is the definition.
(I know that pinch is a kind of steal)
I don't understand the remainder of the clue.
Can you help me to learn more?
(Other definitions for steal that I've seen before include "Plagiarise" , "Take without permission" , "Nick" , "crib" , "Snatch" .)