To become unfastened or undone.
To make loose.
To free from restraint; to set at liberty.
To relieve (the bowels) from constipation; to promote defecation.
To become loose.
To disengage (a device that restrains).
To occupy, detain, keep busy, or delay.
To immobilize a capital: make a capital investment that makes that capital unavailable.
To complete, finish, or resolve.
Don't forget to tie up your hair before you bake.
To secure with rope, string, etc.