Wind instrument missing its second note — make a new arrangement (7)
I believe the answer is:
reorder
'wind' is the definition.
Although both the answer and definition are verbs in their base form, I can't see how one could define the other.
'instrument missing its second note make a new arrangement' is the wordplay.
I cannot quite understand how this works, but
'instrument' could be 'order' (order is a kind of instrument) and 'order' is located in the answer.
'second' could be 're' (prefix meaning second in eg review, re-education) and 're' is found within the answer.
This accounts for all the letters.
This explanation may well be incorrect...
Can you help me to learn more?
(Other definitions for reorder that I've seen before include "requisition another!" , "Send off again for" , "Request for further supply" , "marshal over" , "Arrange afresh" .)