Free, some bound off (4)
I believe the answer is:
undo
'free' is the definition.
(I've seen this before)
'some bound off' is the wordplay.
'some' indicates a hidden word (some of the parts of the word are used).
'UNDO' is hidden in the letters of 'bound off'.
(Other definitions for undo that I've seen before include "Remove the wrapping" , "Cancel or reverse an action" , "set free" , "Cancel -- annul -- reverse" , "Open button or ruin" .)