Bind up (3)
I believe the answer is:
tie
'bind up' is the definition.
(I've seen this in another clue)
This is the entire clue.
(Other definitions for tie that I've seen before include "Bind; be equal" , "'Fasten, with string say (3)'" , "Affiliation" , "A draw or male neckwear" , "Neck attire" .)