To modify a surface such that things will not stick to it
To tie up a capital: make a capital investment that makes that capital unavailable.
To render motionless; to stop moving or stop from moving.
To remove or clear a block or obstruction from.
In whist, to throw away a high card so as not to interrupt one's partner's long suit.
To free or make available.
To enable communication again, via telephone, instant messaging, etc., with (somebody previously blocked).
The removal of a block or blockage.