To allow a bird to fly from the fist.
• (a.) Cast or laid aside; as, cast-off clothes.
To let go.
To let go mooring ropes.
A calculation determining how much space copy will take up when typeset. 
To let go a line, as to cast off a bow line.
To let goto let go of the securing ropes
Cast'-off` adjective Cast or laid aside; as, cast-off clothes. 
An offset of a gun stock to the right, so that the line of sight aligns comfortably with the right eye while the butt of the stock rests comfortably on the right shoulder. Almost all right-handed shooters benefit from a little castoff and most custom built guns are made this way. The only question is how much. The castoff of a gun is about right wh...
To let go.
To let go.
With the bird on the fist, this is the action of pushing it to be airborne.
To throw off a bird from a raised glove
shake off verb get rid of; `he shed his image as a pushy boss`; `shed your clothes` verb make the last row of stitches when knitting
To release the ship from her mooring