A slipknot is a knot that tightens when you pull one end (or the standing part of the rope). The loop can get smaller; that is the “slip.” People use it to tie a bundle, to start some other knots, or to make a loop that will close. You can also dress it so it comes undone when you tug the right end — though actually not every slipknot is meant to release; some are meant to grip harder as you pull. It is a real crafts and scouts word, also used in everyday “tie this so I can pull it tight.” Neutral. Written slipknot or slip-knot; both appear.