knot
at a rate of knots very fast. British informal
☞ A knot here is a nautical unit of speed, equal to one nautical mile per hour.
cut the knot: seecut.
tie the knot get married. informal
tie someone (up) in knots make someone completely confused. informal
1996Daily Star It looks like an open and shut case until the brilliant QC starts getting the prosecution witnesses tied up in knots.