Loosen, like a knot (4)
I believe the answer is:
undo
(Other definitions for undo that I've seen before include "Wreck" , "Loosen; annul" , "Untie or ruin" , "Open buttons or ruin" , "Release button, knot etc" .)
I believe the answer is:
undo
(Other definitions for undo that I've seen before include "Wreck" , "Loosen; annul" , "Untie or ruin" , "Open buttons or ruin" , "Release button, knot etc" .)