(to cause something) to become loose or looser

unbind

(of hair) loose, not tied; (of a book) without a cover

undo

of undo

open

to untie, unfasten, loosen (knots, buttons etc); to destroy (something good) and bring back the (bad) state of affairs that existed before

open

to use a key to open a lock on (a door, cupboard etc)

open; solve

to remove a screw or screws from (something)

set free; unbind